I'm using only Hardcorio mod,

https://imgur.com/a/PIdUWUO

20916.188 Error MainLoop.cpp:1035: Exception at tick 7411314: Error while running event hardcorio::on_tick (ID 0)
LuaUnitGroup API call when LuaUnitGroup was invalid.
stack traceback:
hardcorio/control.lua:581: in function 'group_main'
hardcorio/control.lua:2393: in function 'tick'
hardcorio/control.lua:2652: in function <hardcorio/control.lua:2650>

The error causes the spawn enemy bases. When is too many enemy bases

I'm using only Hardcorio mod,
https://imgur.com/a/PIdUWUO

You cut the mod information on the screenshot, but left the information that this mod was changed by another mod ("Squeak Through"). Are you sure that only one mod is installed ?!

This is a rare mistake. Such errors occur in any modifications due to the implementation of multi-threaded processing. If you open this line of code, you will see that there is a check on the previous line to prevent this error.

Mods: upgrade-planner_1.5.3.zip, Squeak Through_1.2.2.zip, hardcorio_2.3.10.zip, bobinserters_0.16.8.zip