I see this 2 types are wary common so i think this can be changed . First is matchmaking stuck problem . Some times (today more often then yesterday) we got stuck in dominion match making system and we need to do alt+f4 to leave game and start all over again . Solution for this can be simple back button to leave that match making and start it again. Second is nerve breaking , when you finish duel and go back to claim your rewards you get in error message where you get told that rewards will be added on your account later , and that is newer happens ... how to fix that i have no idea but would be nice to fix .
Yeah, simply adding a "cancel matchmaking" button would prevent players from having to shut down the game, even if it doesn't fix the servers.
Secondly, I don't think the servers really do add new items when it displays the "can't access server" message. Naturally, this is not okay especially because of the micro transactions inevitably involved in metal. If you intend to profit off of an in game system, I should hope the system functions normally first. I'll chalk it up to beta servers melting though, as I'm sure it'll be patched up by release.