Running an unsupported version of MediaWiki (1.29) doesn't help. I vaguely remember seeing this kind of corruption on other wikis reported in Support Desk some years ago.

@Ciencia_Al_Poder Looking at the history, looks like from this page (https://wikiapiary.com/wiki/FFXIV:_A_Realm_Reborn_Roleplay_Wiki) onwards there was an issue with saving. Looking at the bot logs, what was sent to the api interface is not what is currently showing on the page. For instance, https://wikiapiary.com/wiki/FFXIVDrops_Wiki has content regarding Terraria... Another page such as https://wikiapiary.com/wiki/Ffxivpedia_Wiki now has data from https://terraria.wiki.gg/wiki/Terraria Wiki; however, my bot only pulls data from fandom.com currently.

Like you have mentioned, maybe with the server experiencing some 503 errors there may have been data corruption at the time? The bog logs show that 10 consecutive errors were returned from the WikiApiary API and the bot automatically shutdown. Want me to run the bot against a single page and see if we can replicate the issue again?

Actually looking further at the edits from the 13th, looks like some are correct and some are to completely different pages, or are now marked as Bot pages. Additionally, looking at https://wikiapiary.com/wiki/Fennipedia_Wiki revision history, 688 bytes were added to the page, yet the page is blank. This has me thinking there might be data loss as you suspected.