I spotted a scenario last night where a filter change didn't trigger an autofocus run.
1. I has a sequence setup in the scheduler with 20xLum, 20xRed, 20xGreen, 20xBlue.
2. The Lum filter had some issues and aborted after the first sub and moved onto Red and correctly auto-focused.
3. When RGB were complete, the sequence returned to the failed Lum but DID NOT auto-focus.
4. At the end of the LRGB sequence, the scheduler correctly repeated (as I had it configured) and started again with Lum. Since it was already on Lum it did not auto-focus which is correct (no filter change).