changing volume using navigation bar on the right side of the screen fails

I have problem changing the volume using the menu bar on the right side by swiping down. when I am using YouTube app and when I am swiping down to bring the menu for changing the volume, sometime wont work. the volume doesn't change and only volume rocker will work. I have to reset the ipad to fix the bug. i updated the ipad pro 11 to ipad os 13.4.1 . the problem still exists. I also updated YouTube app. wont work.

when this happens, the menu shows that the volume is on 100%. but the sound is on 30 to 40 %. only volume rocker shows the right amount.