The issue is every question must have a tag. Those Those tags that do not exist on the target site get removed during migration. So So if none of the tags exist on the target site it has no tags and the the engine would reject the question.
If I am not mistaken it used to be the case that in
in such cases the migrated question would get tagged with untagged so
so the questions would not get rejected in such cases. I am guessing the current situation is the unintended side effect of some other change.
I am guessing the current situation is the unintended side effect of some other change.