With my OPN S1, this is exactly what I did a few years back, turned off the feedback manager.
The tremolo effect is not caused by music or instrument in my case but by the voice of my little 6 years old girl.
The unfortunate thing is that I discovered lately that this remove the ability for the aids to use the built in features to remove more noise in a noisy environment and help with speech.
So I turned it on again lately and with the noise management turned to the maximum it is not that bad as before.
Been 5 years with my OPN S, hopefully when I switch to the Intent in a few weeks this will have been addressed a few generations later.
My audiologist was also taken aback a few years ago when I suggested to turn off feedback management after reading about it here.