Migrated posts lose their pre-migration reputation
Today I asked for (and was granted) migration for a question from SO to Mathematica.SE
When the migration was done I lost some rep on SO, and as I've already capped at the destination site that rep was not gained there. Nothing serious, just a few points.
But I wonder if the same could happen when a heavy voted question or answer (with lots of rep gained over a long time) is migrated. Are all the gained rep over 200 lost forever?