iPhone XS vibration does not work for a few minutes from time to time

Hey guys,

do you have an idea why this is? I've tried all the usual software things like turning vibration off and on again but still it won't work. But after a few minutes it works again. I'm on IOS 14.6 and this didn't happen before that. But could this be a hardware problem? Seems strange because it's so random...

Thank you!