I have few Triggers firing at the same time and sometimes I have noticed that one of the trigger is in acquired state and other trigger are waiting for the earlier Trigger to release it.
After sometime, app server is not responding and eventually it is running into Out Of Memory on weblogic 10.1 with JVM@check_alloc error.
The OOM can't be caused by Quartz, unless you have very low available memory.
Furthermore, if you are experiencig OOM Errors, you should expect all sorts of erratic / unpredictable outcomes of the things going on within your JVM - as threads will be dying at random points in their work.
Lastly, it's normal for only one trigger to be "acquired" at time. Quartz the acquired state means that it has been identified as the next trigger to fire (based upon its next fire time and priority).