Record on live loop channel 1 and saved as the default name (LiveLoop001 or something like that), I did not rename it. Later I loaded that loop into another session as a sample. I decided to use live loop function in that session as well, and when I recorded on the live loop channel 1 it added my additional rhythm onto my existing live loop.
E.g. First live loop was a piano → load into new session as a sample still named liveloop1 → used live loop in that session to add bass → liveloop1 file now contains bass + piano
I know the quick answer is to stop being lazy and name my live loops accordingly, but throwing on your radar.