Post-incident Sumary
To summarize this post, I was seemingly throttled by AT&T for days. See the Original Post for the full write up.
While gathering data for this post and attempting solutions, I changed my LTE router’s APN, which caused it to re-authenticate to AT&T, and after I was re-authenticated I was no longer being throttled. One Hacker News user suggested that re-authenticating may have caused me to route through a different PGW (Packet Data Network Gateway) with a different traffic shaping policy.