Unbalanced teams in team builder

I am a bronze player, and I've been noticing in team builder that every now and then there's a high plat/diamond player on one of the teams while all 9 other players are bronze/silver. I played a game where one of my teammates was challenger last season and D1 96MMR this season, and the game was just not fun because this one player pretty much won by himself. I just played another where I was against a diamond player and my all-bronze team just got slaughtered. Not only that but the diamond player kept calling us "noobs" and telling us to uninstall. Are other people having this problem too? It makes me not want to use team builder anymore.