Halo MCC Insider Regional Matchmaking Not Working

Despite all the regions being checked in the network settings menu, regional matchmaking does not work. Being based nearer to the SEA servers, playing at 8 a.m. GMT +8, I queued for 5 min without a match. When I switch to an Los Angeles VPN, matchmaking finds me a game within a minute. I have repeated this circumstance 3 times and a similar trend persists.