Okay, the title may be a little bit misleading - this is a feature-request. I know why it does this, but I can't say I like it.
See, when a post is migrated from a main site to its meta, we still display this canned message on the finished migration:
migrated from <site> <timestamp>
This question came from our site for <site subject>.
This is still the same community. I'm well aware that the sites are technically different (and the subject, too, is technically different between meta and main), but this is simply confusing and pointless.
Somebody posted to meta instead of main, or the other way around - their question got moved to the right section of the community. Now we have a message there, saying it came from a different site. Sure, it technically did, but this isn't an "outside" question, it didn't "come from" some faraway place - and that's exactly what I see in the visual cue of that notice: It's an outside question.
Personally, I'd prefer we'd just do away with all in-community migration notices, but I'd be fine with toning it down to a simple "migrated from <main/meta> <timestamp>" text somewhere instead of the full (pointlessly descriptive) block notice.