Hi Andrea,
This is indeed issue in new Git version , although you can solve by these two option
Simply do any minor changes like moving flow in microflow that will add change and then commit.
alternatively
Download GitHub , add repository and discard changes from there.
Hope it helps!
-Open the Version Control menu
-Show Changes on disk
-Click on the file 'theme.compiled.css.map'
-You will get a window showing the before (Orange highlight) and after (Yellow Highlight)
-Copy the text from the before and paste it to the after
-Save and Exit the window
Im not sure if this is the best way to go around this but I assume since changing something in the Project then manually changing it back shows no changes, makes this Okay to do.