Hi Roman,
I have (may be) similar issue with my OLM2Pro: Incomplete job on Linux version with grbl Ortur LM2
After a lot of investigation Lightburn team still not answer me about technical aspects I described 
Is your a long job? Is repeatable? In the console (full log) can you see if all gcode commands are sent to the laser machine? Check them against the gcode file you can save as plain text