Overdubbing

While recording a new track (overdubbing) the original instrument track is being recorded into the new track. I want the new track isolated from the intrusive instrument track. I searched for hours to find a solution. Why is the original instrumental track merging with the new vocal track while I am attempting to record the new mono track?

A recent poster had a similar problem. Any of these work for you?

https://forum.audacityteam.org/t/recording-vocals-over-audio-separately/42915/12

Do you like to record YouTube or internet music?

Koz