Hmm 
I have just done what you have done and it works as expected on my iPad Air 4 https://www.dropbox.com/scl/fi/gb4ipb5m41ax0kv20bfqc/Video-24-02-2025-12-01-56-pm.mov?rlkey=qxgl9fmb3fko8b3460avkzw2x&st=5ghks2fx&dl=0
I have an android, not an ios iPad.
I think this may be an Android issue because the procedure works on iOS.
I think another Android user needs to try my multitrack record procedure above, that will determine the outcome.
Mike