This is a known issue with 16.2. It's being worked on.
The problem appears to have been solved with pre-release 16.2.1
On the top of the forums site is a box with 'Search this community'. For a reason.
good news, the phased roll-out of InDesign 16.2.1 has begun.
It will take some days before all users will see this update in the CC Desktop App.
Fixed issues in InDesign
InDesign 2021 (version 16.2.1)
Core feature and workflow
When exporting images as JPG or PNG, yellow horizontal lines are generated in some cases.
Stability and performance
InDesign crashes in some cases when you quit after creating a new document.
( ACP )