Yesterday, I made a relatively minor suggested edit (putting some text in block-quotes) to an answer on English Language & Usage. This was accepted and I got my +2 MIP1. Fine and dandy.
Earlier today, I noticed that I'd lost the points for editing the answer, as the original question had been migrated to English Language Learners. On ELL, the answer now shows as unedited – presumably it is only the "last version" that gets migrated and any edit history is lost.
The loss of two Meaningless Internet Points is genuinely of no concern (I only noticed because one of my answers had been getting see-sawing up/down votes and I was trying to make sense of what had happened).
I'm simply curious about this – whether it's "by design", an oversight, or simply too complicated to do differently. I couldn't find anything on meta about this; the closest I could find was this answer which says you should keep all reputation from a migration, although I suspect that was only considering up/down votes.
By request, this is the answer I edited, with my edits (putting the example phrases in block-quotes) still intact (although the fact it has been edited, and by whom, has been lost).
Below is an screen-capture of my reputation changes (on EL&U) at the time. As can be seen, the question using “them” or “it” as a pronoun for uncountable noun got +2 for editing (an answer) on one day, and -2 for "migrated" the next. I have no reputation changes on ELL.
1 Meaningless Internet Points