I don't know if this is a bug, but the frequency tracking has stopped working for me. When v3.7.9 came out, I check the box to turn it on. I thought it odd that once the box was checked, it turned grey and can no longer be changed. It worked though.
I noticed today, the frequency tracking simply doesn't work. All of the rest of VarAC works as it should.
ok. next thing to try - put it back on 100ms and change on the settings screen the polling interval... to 4 seconds. lets see if that works.