It important to keep in mind that new to ranked players start with a silver 4ish mmr, and furthermore that X 5 of any tier can have an MMR anywhere from (X-1) 4 up to actual X 5 since it's quite difficult to demote tiers. So as is almost certainly relevant in this case, a gold 5 player could have a silver 4 (or 3ish in this case) mmr without being demoted.
Also remember that skill level correlates with MMR, not necessarily with rank. So a gold 5 with silver 4 mmr is just as skilled as a bronze 3 with silver 4 mmr who is just as skilled as a silver 4 with silver 4 mmr, at least in theory.
games broken right now I had silver 3's vs gold 4's and they stomped my team. Even if im smurfing the team is just way too shit compared. Games 50/50 rn