I had some lines with several hundred characters in one of my script files.
First I thought the end of the line was hidden behind the minimap but after deactivating the minimap (View → Minimap) I found out that the line is still cut off. So even by moving the horizontal scrollbar of the editor to the far right it doesn’t reach the end of the line.
If you can’t reproduce it: I’m using Linux Mint 20.3 Cinnamon.