I recently undid an erroneous revision of mine, using the "Undo" option. I've often done this, but this time a previous paragraph ended up with several ordinary spaces replaced by the non-breaking space code  . [[[ https://en.wikipedia.org/w/index.php?title=Wikipedia:Manual_of_Style/Text_formatting&diff=prev&oldid=1012838941&diffmode=source | Link ]]]. I didn't ever edit the paragraph so corrupted; I'm quite sure it's not anything that I did. In the last few months I've come across quite a number of articles with weird unwarranted nbsps; I never saw them before-perhaps they got in the same way while undoing, or due to some other issue in the Wikipedia editing/undoing/saving processes? If this error happens it will almost always be invisible to the user; this case came to my attention because someone immediately reverted the nbsps.

I can't indicate how to replicate the error.