Without “Full TX Setup” enabled the sync switches constantly as with 0.76. In fact I’ve since found that I don’t need AV3 interlacefix turned on at all.
I’ve found there is still an issue where the OSSC can lock to 313p instead of 625i (my TV can’t sync to whatever that outputs) and the interlacefix doesn’t prevent this.
It only happens if AV3 isn’t selected when the Dreamcast boots up. If AV3 is selected when I turn on the DC it will work correctly, even after changing inputs, at least until I power-cycle the OSSC.