Completely un-Balanced Flex Matchup

Just finished a Flex Ranked Game..

My team: Bronze I Bronze II (me) Iron III (Both Irons and non-ranked a 3-group) Iron II Not Ranked Flex (Bronze I solo/duo)

Enemy Team: Silver IV Silver IV Bronze I Bronze II Bronze III

Why the heck are Silver IVs getting matched up against Iron II and IIIs??? I thought ranked matches were supposed to be limited to no player being more than 1 full tier higher than other players. I've seen Iron I's being put in matches with Silver IV's, but Iron III vs. Silver IV is almost a 2-tier difference, which is MASSIVE at this ELO.