Cron rules locks up PI?

Is it possible for Openhab2 to lockup/stop responding due to a bad rule? If I use the rule pasted below, Openhab2 will quickly stop pinging and will require a reboot. In the logfile, I see items going offline just before Openhab2 dies. Examples pasted below.

I switched out the rule pasted below and used a createTimer(now.plusMinutes(10) instead of the cron to work around the issue. Seems to have fixed the problem.

Is this a known issue, or is this a newbie issue? Thx!

var Integer timer_garage_light = 10

```rule "every minute"
 Time cron "0 * * * * ?"
  if (timer_garage_light > 0) {
       timer_garage_light = timer_garage_light - 1

   if (timer_garage_light == 1)

Logs examples:
2018-01-03 21:15:12.288 [WARN ] [andler.ZoneMinderServerBridgeHandler] - [BRIDGE (94da2af1)]: ZoneMinderHostLoad dataset could not be obtained (received 'null')
2018-01-03 21:15:12.356 [ERROR] [andler.ZoneMinderServerBridgeHandler] - [BRIDGE (94da2af1)]: Exception occurred in updateAvailabilityStatus Exception='null'
2018-01-03 21:15:12.361 [INFO ] [andler.ZoneMinderServerBridgeHandler] - [BRIDGE (94da2af1)]: Bridge status changed from 'ONLINE' to 'OFFLINE'
2018-01-03 21:15:40.054 [WARN ] [.whistlingfish.harmony.HarmonyClient] - Send heartbeat failed
java.lang.RuntimeException: Failed communicating with Harmony Hub

2018-01-03 21:16:01.433 [ERROR] [nhab.binding.myq.internal.MyqBinding] - Could not connect to MyQ service Null response from MyQ server

2018-01-03 21:16:09.968 [INFO ] [andler.ZoneMinderServerBridgeHandler] - [BRIDGE (94da2af1)]: Brigde went OFFLINE
2018-01-03 21:16:09.973 [INFO ] [andler.ZoneMinderThingMonitorHandler] - [MONITOR-2]: Bridge 'zoneminder:server:94da2af1' disconnected