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 here (Newsweek source removed from where I was using it in-text in that last para, fixed here) and I also encountered it earlier this week here (HuffPost source removed from last para, 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.

To reproduce: (from T234604)

1. Add some text in the article
2. Move the reference 3 between the 1 and 2
3. Try to save

Result:
The reference 3 gets removed.