So some info for this issue from my end. Issue appears for me at least after the 4th game, changing party leaders seems to fix the issue temporarily for another 4 games.
Platform - PC
Gamertag / Username - McDoogle
Timestamp (with timezone) - doesn't occur at any specific times.
Region - EU/UK
Internet Service Provider (ISP) - EE
Connection type (WiFi, cable) - Ethernet, gigabit.
Game Mode /Map - seems to happen on all modes and maps, including redsec.
Steps to reproduce - I play with friends so find that after the 3rd or 4th game, either myself or the entire squad gets sent back to the matchmaking screen. Changing the squad leader seems to fix the issue for another few games. Almost seems server side related, rejecting the connection due to latency or another reason(maybe anti cheat?).
I do get an error message on certain modes I'll see if I can grab a screenshot. Seems to be a random string of numbers though.
Already completely reinstalled the game, seems too inconsistent to be client related.