@JustinG Thanks for your suggestions. I tried deleting all my rachio things. Then I rechecked my callback configuration, stopped OH, erased my tmp and cache directories and restarted OH. Unfortunately, no change. For example, zone-specific Last Event items remain silent regardless of any activity started on the relevant zones.
I noticed that in my OH logs, the rachio devices appear to rediscovered every 15 minutes: see my log excerpt below. Is that normal? Or is a result of the issue I am experiencing?
2022-07-05 14:17:58.455 [DEBUG] [nal.discovery.RachioDiscoveryService] - Found 1 devices.
2022-07-05 14:17:58.455 [DEBUG] [nal.discovery.RachioDiscoveryService] - Check Rachio device with ID 'adf2d13f-c67a-4f2d-9204-8d666fcd1fff'
2022-07-05 14:17:58.455 [INFO ] [nal.discovery.RachioDiscoveryService] - Rachio device discovered: 'Rachio-BDE9CA' (id adf2d13f-c67a-4f2d-9204-8d666fcd1fff), S/N=AC5364343, MAC=009D6BBDE9CA
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - latitude=45.8473891, longitude=-72.3559189
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - device status=ONLINE, paused/sleep=OFF, on=ON
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - Found 8 zones for this device.
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '6f0c451c-1166-4279-8b2e-beafe915bd62'
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#6 'Zone 6' (id=6f0c451c-1166-4279-8b2e-beafe915bd62) added, enabled=OFF
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 6 '6f0c451c-1166-4279-8b2e-beafe915bd62' is disabled, skip thing creation
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '6d6391cb-a2f8-4d88-9ee0-85c41e87d8cd'
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#1 'Zone Gazon' (id=6d6391cb-a2f8-4d88-9ee0-85c41e87d8cd) added, enabled=ON
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '78d4eec3-6800-49b9-afd2-6f67dc512515'
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#7 'Zone 7' (id=78d4eec3-6800-49b9-afd2-6f67dc512515) added, enabled=OFF
2022-07-05 14:17:58.456 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 7 '78d4eec3-6800-49b9-afd2-6f67dc512515' is disabled, skip thing creation
2022-07-05 14:17:58.456 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '88c9df12-7d10-40af-834d-af2f51715a5c'
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#2 'Zone Plates-Bandes' (id=88c9df12-7d10-40af-834d-af2f51715a5c) added, enabled=ON
2022-07-05 14:17:58.457 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '484bbf05-e7d2-477c-8429-2445e692ebfb'
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#5 'Zone 5' (id=484bbf05-e7d2-477c-8429-2445e692ebfb) added, enabled=OFF
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 5 '484bbf05-e7d2-477c-8429-2445e692ebfb' is disabled, skip thing creation
2022-07-05 14:17:58.457 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '26ec8496-4d8d-4294-a527-9fd98e725fe2'
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#8 'Zone 8' (id=26ec8496-4d8d-4294-a527-9fd98e725fe2) added, enabled=OFF
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 8 '26ec8496-4d8d-4294-a527-9fd98e725fe2' is disabled, skip thing creation
2022-07-05 14:17:58.457 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID 'c64bac95-2e17-47a4-8586-7661e54c55eb'
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#4 'Zone 4' (id=c64bac95-2e17-47a4-8586-7661e54c55eb) added, enabled=OFF
2022-07-05 14:17:58.457 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 4 'c64bac95-2e17-47a4-8586-7661e54c55eb' is disabled, skip thing creation
2022-07-05 14:17:58.458 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '5c01427c-511b-444f-b201-0f580d5757fc'
2022-07-05 14:17:58.458 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#3 'Zone Avant' (id=5c01427c-511b-444f-b201-0f580d5757fc) added, enabled=ON
2022-07-05 14:17:58.458 [INFO ] [nal.discovery.RachioDiscoveryService] - 1 Rachio device initialized.
2022-07-05 14:32:58.467 [DEBUG] [nal.discovery.RachioDiscoveryService] - Found 1 devices.
2022-07-05 14:32:58.467 [DEBUG] [nal.discovery.RachioDiscoveryService] - Check Rachio device with ID 'adf2d13f-c67a-4f2d-9204-8d666fcd1fff'
2022-07-05 14:32:58.467 [INFO ] [nal.discovery.RachioDiscoveryService] - Rachio device discovered: 'Rachio-BDE9CA' (id adf2d13f-c67a-4f2d-9204-8d666fcd1fff), S/N=AC5364343, MAC=009D6BBDE9CA
2022-07-05 14:32:58.467 [DEBUG] [nal.discovery.RachioDiscoveryService] - latitude=45.8473891, longitude=-72.3559189
2022-07-05 14:32:58.467 [INFO ] [nal.discovery.RachioDiscoveryService] - device status=ONLINE, paused/sleep=OFF, on=ON
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Found 8 zones for this device.
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '6f0c451c-1166-4279-8b2e-beafe915bd62'
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#6 'Zone 6' (id=6f0c451c-1166-4279-8b2e-beafe915bd62) added, enabled=OFF
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 6 '6f0c451c-1166-4279-8b2e-beafe915bd62' is disabled, skip thing creation
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '6d6391cb-a2f8-4d88-9ee0-85c41e87d8cd'
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#1 'Zone Gazon' (id=6d6391cb-a2f8-4d88-9ee0-85c41e87d8cd) added, enabled=ON
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '78d4eec3-6800-49b9-afd2-6f67dc512515'
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#7 'Zone 7' (id=78d4eec3-6800-49b9-afd2-6f67dc512515) added, enabled=OFF
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 7 '78d4eec3-6800-49b9-afd2-6f67dc512515' is disabled, skip thing creation
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '88c9df12-7d10-40af-834d-af2f51715a5c'
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#2 'Zone Plates-Bandes' (id=88c9df12-7d10-40af-834d-af2f51715a5c) added, enabled=ON
2022-07-05 14:32:58.468 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '484bbf05-e7d2-477c-8429-2445e692ebfb'
2022-07-05 14:32:58.468 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#5 'Zone 5' (id=484bbf05-e7d2-477c-8429-2445e692ebfb) added, enabled=OFF
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 5 '484bbf05-e7d2-477c-8429-2445e692ebfb' is disabled, skip thing creation
2022-07-05 14:32:58.469 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '26ec8496-4d8d-4294-a527-9fd98e725fe2'
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#8 'Zone 8' (id=26ec8496-4d8d-4294-a527-9fd98e725fe2) added, enabled=OFF
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 8 '26ec8496-4d8d-4294-a527-9fd98e725fe2' is disabled, skip thing creation
2022-07-05 14:32:58.469 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID 'c64bac95-2e17-47a4-8586-7661e54c55eb'
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#4 'Zone 4' (id=c64bac95-2e17-47a4-8586-7661e54c55eb) added, enabled=OFF
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#Zone 4 'c64bac95-2e17-47a4-8586-7661e54c55eb' is disabled, skip thing creation
2022-07-05 14:32:58.469 [DEBUG] [nal.discovery.RachioDiscoveryService] - Checking zone with ID '5c01427c-511b-444f-b201-0f580d5757fc'
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - Zone#3 'Zone Avant' (id=5c01427c-511b-444f-b201-0f580d5757fc) added, enabled=ON
2022-07-05 14:32:58.469 [INFO ] [nal.discovery.RachioDiscoveryService] - 1 Rachio device initialized.
2022-07-05 14:47:58.479 [DEBUG] [nal.discovery.RachioDiscoveryService] - Found 1 devices.
2022-07-05 14:47:58.479 [DEBUG] [nal.discovery.RachioDiscoveryService] - Check Rachio device with ID 'adf2d13f-c67a-4f2d-9204-8d666fcd1fff'