There is a posting on zniffer (I think under solutions in the forum) set-up earlier in the year, but since the device appears to be set-up correctly and from your debug log, I see good and fast zwave communication it don’t think it will help here, although it is a good idea for your next project.
I looked at my GE switches and they do not have Association groups either. (just noticed this after many years). Anyway they work fine. Not that it matters, but they are not Zwave Plus devices, just regular Zwave and only transmit at 40Kb, not 100Kb like zwave plus
Separately I’m wondering if adding the metadata “auto-update” to the switch “item” might help.
Bob
Edit: Link to Zniffer instructions and other useful info