more info: here's some supporting evidence suggesting that it is a vst3 issue. here, 2 instances of HY Filter3 are loaded: the vst version and the vst3 version, since i had both.
after hitting play and having the play cursor pass over the AI, if you then stop and move the edit cursor to earlier in the project, the parameter does not adjust to the next AI point.
sorry for the large licecap