Here is a weird one:
I edited https://doc.tiki.org/Tiki17 a few times and I got:
504 Gateway Time-out nginx/1.12.0
That is not a big problem, but perhaps a symptom.
Then, when I check the history, I see that 4 revisions are missing (74, 75, 76, 77)
When I compare, I notice some edits which are mine, and some which are not mine:
It's as if the revisions have been deleted, but I didn't delete them. It's as if the time out saves the data but forgets to put the previous version of the page in the history (or something like this)
I am 99% sure it's a regression, because otherwise, it would have been noticed sooner.
Someone with server access to doc.tiki.org may need to look at the logs...