here you go, it only happened with the sport shop, i havent encountered this when buying up other shops.

https://www.dropbox.com/s/snr7a6ho6kqol44/CHAL_002.SAV

Could you send me the saved game?

So i started the challenge 6 game.

I bought a profit making sports shop from another corporation. All units (except advertising ofc) were lvl 9.
After i bought it the lvl of the units changed down to lvl 8 (no idea why..)
So i upped the training slider to get them back to lvl 9. But then i noticed as seen in the picture below all employes are already red (so trained..) but the units dont switch to lvl 9...