MTBF/MTTR trigger doesn't work properly occasionally

I have this strange problem with my model of a hospital ER made Flexsim. I have a break schedule that should fire at stated intervals and nurses receive a preemptive TS. The nurses state changes to 'breakdown' and a location is set. Here is what happens wrong once in a while.
1.) Sometimes at random MTBF MTTR events, the downobject returns NULL causing an error in the system.This happens once in maybe 20 model runs. If you are a 'lucky de-bugger' you might notice this error every once in a while.
2.) Although the nurse does go on break the setlocation command fails to do its job and you can see nurses standing in the middle of the model even though its on a break. This can be an embarrassing situation especially if you are showing the model to a client.These errors are completely random and there is no way I can replicate them in order to debug them. Whatever I found I have already mentioned.
If somebody is interested to give it a shot I can share the model.

Try and get the model to repeat first of all. The event log can help you see where it's going wrong.

Even if the model does not repeat, does this mean that the model logic goes bad only for a few values of number streams? Is that even possible?
I remember someone at Flexsim who helped me earlier with this problem tried it by removing dynamic stream values and by getting the model to repeat as you said but still was not able to find out the problem.

Turn on repeat streams, and ideally remove the dynamic stream values - then if it still doesn't repeat, try and find out why looking at the event logs of two runs that should be identical (ie. same replication, scenario and streams). Often it will be: labels,variables and tables you're using that are not reset; non-draw related logic in the on-draw code; not updating kinematics correctly, or simply not having home network nodes or reset positions for task executors. If you get an exception error in the console, then that can sometimes also cause it not to repeat. In that case, try reopening Flexsim with the model and find when the exception occurs.

When you have an error that is repeatable every time, or can't determine why it's not repeating (having tried the suggestions above) - send it to support or post the model here and we'll help.

Good luck!