Alert slider issue via OnePlus 7T

  1. E1590365518065
    Cupcake Nov 25, 2020

    E1590365518065 , via OnePlus 7T , Nov 25, 2020 :
    Hello, for many months my alert slider isn't working properly on my oneplus 7t 256gb HD1900.
    When I put the phone on ringmode, it stops ringing and vibrating by itself, when I get phone calls , this happens without me ever touching it.
    I have to put it in top position ( silent mode) and back to ring mode for it to work again, but after a few hours or sometimes even minutes it stops ringing again.
    I tried to change cases, not using case, carefully looking if perhaps it changed modes cause of accidental touches, but no, it stays in ringmode always but without ringing. It also never changes the screen information of the mode that it is using without changing modes on the slider.
    The information of the used modes correspond to the alert slider positions, it's just the sound options that do not correspond ( while beeing in ringmode it doesn't ring or even vibrate).
    I often noticed that, after reserving the modes, if I press any of the volume buttons it stops ringing ( even if it is with volume, eg: 50%), I think that is not normal (accidental volume button touches are much easier to happen).

    I need to get this problem fixed, it has caused me problems even at work, cause get missed calls even with the phone iny hand, cause I does not ring or vibrate...