Just a small query.....have you tried updating the camera app ?
Try updating your camera app once bcoz I just checked my 7Pro and I am using an upgraded version(6.4.66)
Leaving a screenshot for you to see :
View attachment 1750528
Even after updating if the issue persists then please visit your nearest OnePlus service center in order for them to figure out what the actual issue is, so that they can resolve it.
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