I know i had a similar issue with a OnePlus 3T, the sidebuttons are just glued to the side of the frame on the OnePlus 5T aswell right?[br]
Anyways, my buttons wouldn’t stick to the side very well so i put my own double sided tape strips there, but the strips were too thick and that made the volume up button get pressed all the time when i sealed the phone up. So i simply removed my double sided tape and used B-7000 glue instead and that fixed the problem.