Prediction error with single standard jumps
At very high ping (250+, sometimes might be noticeable to some people at lower pings) when standing still and tapping jump then waiting to land before pressing it again, on some jumps the camera flashes out of sync and then back into sync with the player's movement. It can be reproduced much more easily at high ticrates, so it's probably a frametime-dependent problem. It can happen in listen with cl_netlocalping, and with "real" latency on a dedicated server.
I noticed it when working on new predicted physics features, but can reproduce it in current master also.