Multinstance bpm produces Implicit flush due to query execution

Hi, we being using BPM Activiti for a long while, but now in production we having some wrong assignments in the ProcTask creation, we suppose due to the volume of simultaneous users. The problem become when executing a multi-instance task that causes “Implicit flush due to query execution” and apparently some procActors are wrong assigned to ProcTask (in the attached image same Actor is assigned repeatedly). We want to known the impact of “Implicit flush” can have on data, and if this debug warning can be the cause of wrong assignments.
As i said before in test enviroments this works correctly.

Could it be that for this particular process instance you had multiple process actors for the same process role with the same user?

Hi, yes this process had multiple actors for the same process role and only one user can initiate the process. this works fine in a test environment, but when many users work simultaneously something breaks resulting in inconsistent data.

I meant for this particular process instance where the error occurred, could it be the the same user is defined for the role multiple times?

Like this:

Hi, no, process actors are created correctly just one time for each user, i verified table with a query for the process instance ID.
The problem occurs randomly with process tasks.
I have been able to find cases where running two multi-instance BPM processes at the same time caused inconsistency in the process tasks.
And the same case doing it one by one did not produce any inconsistency. I have done this on a local machine with the debugger.

One important thing is that these processes run with many actors involved. The execution of tasks takes time due to the number of actors. However on a local development machine it only takes a few seconds.