I’m seeing outbound traffic from T-Mobile US users in the midwest route traffic to SEA for an app running in IAD+EWR on the 2a09:8280:1::/48 anycast subnet, and the traceroute shows traffic routing over Lumen with the following BGP communities:
174:991 1299:10050 3257:1970 3356:3 3356:22 3356:100 3356:123 3356:575 3356:903 3356:2012 4213:20854 6453:90 17152:1 large:64219:1002:3697 large:64219:1900:0 large:64219:1903:9
It looks like 3356:2012 may be causing this route to be sent all the way to Seattle, which originates at a Lumen router in DTW (less than ideal when there are closer PoPs).