We can not give any guarantees that save files from 1.1.x will be working in 1.2 without issues which is why we recommend that you roll back your game to the previous version and finish any ongoing games you want to finish before updating to 1.2. More information on rolling back your game version can be found here! (TL;DR is go to properties in Steam -> Betas -> select the version in the dropdown list).
Yes, this game started under the current patch.Was this game started under the current patch 1.2.4 ? Or a previous one?
From the patch notes: