I could sorta see a situation where the reality is "we're in the middle of a miserable transition and it'll clean up when we're done" but I don't think anyone has confidence that's all it is at this point.
Everywhere I’ve worked, if a migration is causing this much downtime then you kill the migration or slow it down. If every change has a 10% chance of bringing the site down, you only do a change every week or two until you can work out the kinks.