Just FYI that this problem is still happening. Walmart split my order into four packages delivered today. One was delivered this morning and the rebate credited right away. Three boxes were delivered this afternoon and I only got one rebate out of four I expected. The missing three items were in a separate box from the one that posted. I sent in a ticket but had hoped this had been fixed.
I definitely flagged this case last time, although I didn't hear anything about it being resolved. This is mostly on Walmart's end, we just process the data once they send it over.
Thanks for updating this though, I'll follow up with the team that was looking into it.