And only until I press Enter one time after the ‘c’, then it switch to “LF Only (UNIX)”

Oops, an amendment: You need to close & reopen the document between steps 3 and 4. Then, it’s not temporary.

The “Tools > Customize… > Status > Return Method” has nothing to do with this situation at all as it seems.

It has nothing to do with the cause. But you’ll be hard pressed to see the problem if you can’t see what the Return Method is in the status bar.