My first thought was to just block migrations altogether. We already do this when questions are older than 60 days, so there’s some precedent for it. Certainly, it will only have a minimal impact on Stack Overflowon Stack Overflow1:
Looking at the questions migrated away from English Language and Usage (mostly to English Language Learners), it seems they are often not answered or much upvoted before migrationbefore migration:
On the destination siteOn the destination site, they tend to be voted on and answered: