QuoteI player this save for several weeks without any Issues but after the latest Update
That's why i never let anything update at their own for an existing colony unless i encounter some error's and know what mod cause it. That the the curse and blessing of the steam update service.
Basicly a BAD idea, to use a moded 1.2 game at 1.3. The chances that that work are mosttime very low. That only work's for vanilla savegames.
Reverting a 1.3 to 1.2 shouldn't work anyway.
When you still got an original 1.2 savegame, you should use Rimworld 1.2 with that modset (unless some modder made a mistake with updating his mods).
Try to eliminta error's before you start a colony.
Read mod description, to get hints where to put mods (rocketman).