Geant4 version 10.3 and 10.5 compatibility

I used to work with my code under version 10.3 . Now, after update to 10.5 instead of one (expected) output file, I got three of them (_t0,_t1… etc) . I guess it is some issue of multithreading and not merging all ntuples to one tree. What is the problem, and what I have to change now?

Thank you