Bad teammates AFTER winning promos

I got no problems with teammates in promotion series. Nor before that.

The problem is after I win and get promoted (ex. Gold IV). Instantly, all lanes losing. Got people playing in gold looking like they belong in bronze 5 (no game sense, constantly dying, doesn't look at map, etc.). EVERY lane is losing, I kid you not.

Any one else get this? I've been promoted and demoted about 8 times from gold IV, all the bad games are after I get promoted. Of course I get demoted right after and suddenly my teammates are competent.