fulcrum service exception (concerning NMTrigger) , possible cause and possible workaround ...

Hi.
today i got a weird exception when starting up my company scarab. It 
worked for months without
any errors. Suddenly i saw this in catalina.log:
...
Caused by: org.quartz.ObjectAlreadyExistsException: Unable to store 
Trigger with name: 'NMTrigger' and group: 'Scarab', because one already 
exists with this identification.
        at org.quartz.simpl.RAMJobStore.storeTrigger(RAMJobStore.java:309)
        at 
org.quartz.core.QuartzScheduler.scheduleJob(QuartzScheduler.java:652)
        at org.quartz.impl.StdScheduler.scheduleJob(StdScheduler.java:249)

Where would i have to lookup this trigger object ? It first looks like a 
configuration problem, but i did not change anything there...
This exception was thrown whenever i make a call to scarab/issues . The 
effect appears right away after startup of scarab.

I remembered, that this morning we changed from nfs mount at boot time 
to automount, so i digged there...
no obvious connection found here.

Then i found this scarab issue #SCB1750 ... and i scratched my head 
about what i read there haha.
I have done something there 2 years ago to avoid such problems? i dont 
remember this...
So the boomerang came back ?  well...

By chance i removed the index folders and restarted scarab...
since then it works again. magic ?

regards, hussayn