Mmr bug?

So I'm plat 3 with a healthy mmr. Even though there is no way to check exactly what, I know because I'm gaining 21lp per win and 16 per loss. So I keep getting matched with silver 1s who have a 46% wr and I noticed a record of feeding. This happens every one in a while. How can matchmaking allow this? Is this a bug because of mmr restructuring?

Tldr: getting matched with silvers when my mmr is much better 100%