I really was suspect of my network, it's complex: mixed 10G/2.5G/1G switching, Mikrotik router with "bypassed" fiber feed (via a custom PON instead of the AT&T router), two backup internet feeds, Aruba WiFi, etc... it's not normal 🙂 So I really wanted to elimiinate that from the equation.
So I did just that... I took my laptops on macOS 14.3 and also an older Window 10 PC and did two tests:
- USB 2.5G Ethernet adapter right into the BGW320-500 router supplied by AT&T -- no router bypass, extra routers, etc... just what AT&T supplies
- Tethered to TMO cellular on an iPhone
... and it still happens when using QUIC + IPv6 in all the above configurations. If I force IPv4, it's fine even across QUIC.
Browsers:
- Brave: Version 1.62.162 Chromium: 121.0.6167.164
- Chrome: Version 121.0.6167.160
I'm really stuck now, hoping someone else can replicate my findings and maybe this can feed a bug report of some sort. Really curious that for me MS Teams seems to behave better not on QUIC, but maybe that's because it's based on Chromium as well!