I've noticed on two different days recently, that the arcanawiki (and I'd guess all of wikidot) is having a strange bug, that could cause us to lose content if we're not careful.
Basically, if you save a page, and then re-open it within a few minutes to make another edit, it is sometimes not opening the new version you just saved, but instead opens the previous version. So then if you make a change and save it, the previous edits are either lost or hidden in the page history.
As near as I can tell, the way to avoid this is to wait a few minutes between edits. Eventually, the changes you made propagate to the editing function. I haven't played around with it enough to figure out if its an issue with a specific browser, or if it can be fixed by just clearing your cache / reloading the page. It's only happened a few times that I've noticed, but I imagine it'd be easy to miss if the previous edit was small, and/or was done by someone else.
The best work-around is probably planning out your changes in advance so you don't have to re-open the page twice in a row to add the little thing you forgot on the first draft.
If editing a page that someone else has recently worked on, please take a moment to visually inspect it and make sure that the version you've got open isn't missing anything. Thank you.