@Kbrown said that she tried to create a page in VisualEditor on office.wiki during the editing outage. She got 503 errors for a couple of minutes. After a few tries, the page opened and gave her the expected warning about the wiki being in read-only mode.
To be clear, you tried viewing a page like https://office.wikimedia.org/w/index.php?title=Does_not_exist&action=edit&redlink=1, and instead of a wiki interface, you got an error page like the below?
If so, this probably wasn't related to VisualEditor (or MediaWiki), I think these errors are generated by load balancers or something. I also don't see anything that would point to VisualEditor in the error logs around that time (Logstash).
No, I got a pop-up dialog box (browser-style, not one of VE's own pop-ups) on top of the VE window, and it was much less verbose than the usual 503 landing page. I believe it said something like "Error: 503 [something something]" - 4 or 5 words total. Apologies for not having a screenshot or a better memory of it - at the time I assumed it was expected behavior during the planned outage, so I didn't think much of it until Whatamidoing told me otherwise afterward.
I guess it's a 503 from one of the API calls we use then, rather than the page itself. Still, probably not a VE or MW bug, but something with the server setup – I don't really know if these errors would be expected during the switchover. Thanks for responding.