Interesting.
…because it looks like the duplication bug is related to the “ä” combination of symbols.
For me, it appears like this, so I don’t see those “symbols”:
f376ba2a-fec2-4b85-ab2d-c1996c68acd6-image.png
…and I don’t show it, but trust me, my status bar says the encoding is UTF-8, just like yours does. If I edit and save this file, this character doesn’t “grow” like it does for you.
So I’d say it is some sort of odd encoding issue (for you), but we’ve got UTF-8 in line 1 of the file, and also in the status bar, so
I’m mystified.
I will say it made me think of some other encoding issue I read about recently HERE. But I think that is just a curiosity, not related.