Here is a server update with some matchmaking bugfixes, as well as some improvements. The rare game start delay issues should now be fixed, with the removal of some server locks. The locks were likely responsible for many issues. There were requests to not mix parties and solo player. We've addressed this by making parties of 2 always play 2v2 and parties of 3 always play 3v3.
Please keep reporting issues, as they have been quite tough to track down.