Reported by Kerry Raymond on enwiki:
"I was trying to add some content to the end of the [[ https://en.wikipedia.org/wiki/Martin_Love | Martin Love ]] article. I went to the bottom of the article and couldn't seem to be able to get a text cursor to appear (clicking there didn't seem to work, possibly because of the presence of a template?) but then the VE suddenly offered up "+ Insert paragraph" so I clicked that and added my content (which was a cut-and-paste of some existing content as I was reordering the sections). Everything looked OK on screen and I saved it. I then opened it in the source editor and found that the cut-and-paste material had been placed under the Categories. [[ https://en.wikipedia.org/w/index.php?title=Martin_Love&type=revision&diff=673363926&oldid=673363774 | See the diff ]]. I don't know if it matters where the categories appear within the article, but I think it's going to enrage the source editors if VE users start "putting" the categories into the middle of the article as it is evidently possible to do when you add content at the end of the article, noting that the source editors will probably assume that the VE users did it deliberately/carelessly as they will be unaware that VE users manipulate the categories in an entirely different way."
Categories should be kept at the end of the article with the possible language links, rather than adding article content after them.