When the editor option "Enter Play Mode Options" is checked, and "Reload Domain" and "Reload Scene" are unchecked, dynamics / contacts no longer work in play mode after the first session.
This is because VRCAvatarDynamicsScheduler._latestCompletedFrameNumber is not being reset to -1 when domain reloads are disabled, so the next time you enter play mode, it has to wait until the frame number of your last session before SignalFrameComplete gets run again.
These play mode options are selected by default for all projects using VRCFury, so this is a very widespread issue.
This is a new issue in 3.7.6.