Hello,
I got tier 8 this week and Forza Hub realized it. But I only got the money for tier 7 this week. Is it a bug and could you look after it please? Thanks a lot. 
it will take a couple of days but then you will be able to claim a differential reward payment for moving up in tier. Its kind of an annoying system. Keep an eye on it during the next week because if you let next week’s full rewards payment come in it will bump the differential payment out.
That is correct that it takes a couple of days to catch up.
Thanks,