I got a Galaxy Rab A11 plus just after Christmas. I absolutely love this tablet. However, I've noticed a very intermittent issue. Whilst the tablet is in a mount that's attached to an arm attached to my headboard, I like to watch YouTube. On more than 3 occasions now, during a video, the touchscreen suddenly accepts no input and I have no control over the screen. If I put the tablet to sleep and then immediately wake it up, all is fine again. I initially thought it was the case the tablet was in whilst in the mount, so I used the tablet naked in the mount. The issue happened again. Interestingly only ever in YouTube.
I really hope thos isn't a hardware issue. I've never seen the issue when using the tablet both outnofbthe mount and not using YouTube.
Any ideas?
Photos included are the mount and the case.

The mount i use. The tablet is in landscape when attached

The gell case.