I'm having the exact same issue, almost every game I play I get a bug splat at the end. I'm able to join the end game lobby about 50% of the time but most people are already gone by the time I get in. This is really annoying for me as me and my friends have a habit of getting really chatty with both team and its quite often we queue up with at least 1 or 2 people from the previous game. For me it's been happening ever since
release. This seems to be happening more and more with new champion releases. I'd honestly rather you keep the champs on the PBE until you fix all these terrible issues.
I've gotten so annoyed with the bug splats that I've begun coming up with new and creative things to type into the message part of the bug splat.
EDIT: If any of the rioters want some bug splat numbers I'd love to play a couple games and get some for you