That’s the unfortunate problem that Blizzard presented when trying to find a balance of strict matchmaking with allowing friends to play comp with each other.
And in Season 1 (back when there was no rank emblems and it was 1-100 instead of 1-5000), the spread allowed in groups was MUCH worse. The max spread was 50 (and it was abused by a few South American players in the NA ladder), so you saw 80s (the equivalent of high-master/GM today) grouped with 30s (the equivalent of approximately high-bronze/low-silver).