If add ANY mod in saved game, then i can't load saved game. I can't add some mods after start game, because rpgsystem will broken. I tried disable rpgsystem, save, and enable - no error - but my speed is extra high. (player have 0 xp).

error message after adding fnei mod:
Error while running on_configuration_changed: Error while running event RPGsystem::on_research_finished (ID 18)
RPGsystem/control.lua:812: attempt to perform arithmetic on field '?' (a nil value)
stack traceback:
qol_research/control.lua:146: in function 'update_for_force_and_entry'
qol_research/control.lua:168: in function 'update_for_force'
qol_research/control.lua:178: in function 'update_for_all_forces'
qol_research/control.lua:328: in function <qol_research/control.lua:286>

more bugs. I update some other mods (not add mods) and i can't load saved game!

Error while running on_configuration_changed: Error while running event RPGsystem::on_research_finished (ID 18)
RPGsystem/control.lua:812: attempt to perform arithmetic on field '?' (a nil value)
stack traceback:
qol_research/control.lua:146: in function 'update_for_force_and_entry'
qol_research/control.lua:168: in function 'update_for_force'
qol_research/control.lua:178: in function 'update_for_all_forces'
qol_research/control.lua:328: in function <qol_research/control.lua:286>

i disable mod "Quality of Life research" and enable this mod - game load is ok. speed is ok.

There is some incompatibility with Quality of Life mod.
I'll check that