It used to be I could click and drag the superscript inline citation to move it to a new location. A few times now I've tried to do that and the citation just disappears entirely, and can't be retrieved by ctrl-z. It happened just now [[ https://en.wikipedia.org/w/index.php?title=Jacob_Wohl&diff=prev&oldid=919501858&diffmode=source | here ]] (//Newsweek// source removed from where I was using it in-text in that last para, [[https://en.wikipedia.org/w/index.php?title=Jacob_Wohl&diff=prev&oldid=919501916&diffmode=source | fixed here]]) and I also encountered it earlier this week [[https://en.wikipedia.org/w/index.php?title=Seven_Graham&diff=prev&oldid=918252613&diffmode=source|here]] (//HuffPost// source removed from last para, [[https://en.wikipedia.org/w/index.php?title=Seven_Graham&diff=next&oldid=918252613&diffmode=source|fixed here]]). It doesn't happen every time I move a citation, but it has happened to me at least three times now, I believe.
I'm currently using Windows 10 and Chrome 77.0.3865.90. I think in the second edit I was on my laptop, which would be macOS Mojave and the latest or near-latest version of Chrome.