Quartz 1.6.1 and Spring FW 2.5.6 Jobs Stopping

So for a while I've been trying to track down why my jobs running on a org.springframework.scheduling.quartz.SchedulerFactoryBean seemingly stop quite arbitrarily and in groups of Triggers contained within each SchedulerFactoryBean. No exceptions are being thrown from application code and there is no advice setup on the application classes. Application code completes before the job not running correctly again.

I recently decided to try upgrading Quartz as the library I was using was rather old. Quartz 1.7.3 was installed and this problem has not been experienced since. Sorry for the lack of great insight into the cause here, but hopefully my experiences will help put the minds to rest of those being driven similarly insane by this problem.