I swear I've made like 5 posts about this.
They're not actually silver 1. You're not actually gold 1. They're previous plats like you who happened to get placed lower but their MMR is still plat. Even though ranks were reset MMR remained
It's too early in the season for divisions and mmr to have equalized across all players since most people haven't played enough
I'm currently "Plat 5" despite every game having Diamond borders across both sides, and that's cause my rank reset but MMR remained Diamond 5 and I haven't played enough to reach the division that mirrors my MMR, hence the +30lp wins and -14lp losses