When I add a new track and set the volume at a certain place, randomly it switches to mute for some reason. When I unmute, it switches back to mute. Wondering how to regain control of volume settings...

Hi SongScuffler - Usually when unintended volume changes happen in a song, it means there's some hidden Automation somewhere in the track. If you hit the "A" key, GB will display the Automation lanes for all tracks -- if you see some unwanted Automation data in there, you can just select and delete it. The video below covers Automation briefly..

I have checked automation and there is none on, on this song... but random muting is still happening. I noticed that a little yellow circle pops up in the time signature box when the volume goes out.

Hi SongScuffler - Hmm, the closest thing to a little yellow circle I see in GB is the little yellow headphone icon which is the Solo button on each track. When a track is soloed the time signature box text turns yellow [in fact all the text up top turns yellow to warn you that something's soloed], but no dot [of course you may be working in a different version of GB]..