That is strange. Is the T-Mobile hotspot connected to eero's also?
Thanks Deepak. No, the hotspot was my cellphone and WiFi on the phone was disabled, as it usually is.
Is it possible for you to connect up eero's to tmobile hotspot and see if you are having the same issue?
No, eero WAN connection must be wired ethernet. It can't be a wireless repeater.
Along your train of thought, I went a step further this morning, and removed eero from the network entirely, took the ATT router out of bridge mode and connected Core directly to ATT router by wire. Rebooted ATT hardware and Core, but no change.
I will admit my conspiratorial tendencies did pop up this morning, when I thought that Softbank is largest investor in Tidal and they own Sprint, which is trying to merge with T-Mobile. So Tidal might give preference to streaming requests originating on T-Mobile network to please their future masters?
More likely, being broke, nobody at Tidal is monitoring their quality of service anymore. Maybe the network engineer wore a MAGA hat to work.