https://en.wikipedia.org/wiki/TCP_congestion_control#TCP_BBR

List some issues, but only earlier version, not BBR3

BBR1:

researchers like Geoff Huston and Hock, Bless and Zitterbart found it unfair to other streams and not scalable.

Hock et al. also found “some severe inherent issues such as increased queuing delays, unfairness, and massive packet loss” in the BBR implementation of Linux 4.9.

Soheil Abbasloo et al. (authors of C2TCP) show that BBRv1 doesn’t perform well in dynamic environments such as cellular networks.