The best way to catch someone out in a repertoire like this is not to find a line that is actually bad but a line that ends in a position that the computers and GMs like but is hard for an amateur to play well. This could be a position with a good computer eval that the GM glanced at and said "yeah, looks fine" but actually depends on a tactical nuance that is hard to find over the board, or it could just be a position that has some important explanatory text about how to proceed that your opponent is likely to forget if they have just been memorizing the moves themselves. Of course, this takes a fair amount of human work as well as access to the repertoire in question.

Hi.

My FM clubmate told me some time ago that the end positions in some lines of Shankland's semi-slav where not to impressive. That's about what I can say as I don't remember specifically what positions were referred to. We then looked at possible deviations for a while, using a correspondence database and got progressively more depressed (but I recovered ).

There was a very interesting corr game we found that white actually won in style though. Sadly it was for a non-main move continuation and by the time I am writing this solutions may already have been found.

Have a nice day.