It does happen, I buy maybe 2-3 scouts a season, and have had a few that perform really badly. Even had one once that I gave a good run of games etc and he became World Class (24 y/o), his form didn't pick up and I sold him.

I have tried just buying very good 5* and training them up, but have decided on the whole, overwhelmingly the scouts are worth it.

If you only buy the odd one, and he sucks, that's a big hit though.