Since the start of this season the below has been happening in 50% - 70% of my comp games. It has also been the other way around where i play with golds against an entire team of silvers. I read somewhere this has to do with hidden mmr because i was plat 3 last season or something like that since. Could someone explain this a little more to me?

https://imgur.com/a/mh6hHvO