Thank you for your message.
Unfortunately, our developers are still testing this issue out. However, we've received reports from a couple of other users, that updating their iPad OS and/or re-installing Viewer app had helped them to resolve the issue, so perhaps something in the subsequent iOS was fixed which, in turn, helped to fix the issue.
Could you please make sure that your iPad is updated to the most recent available version 16.2? In addition, please also try uninstalling Viewer app from your iPad and then re-installing it once again.
Let us know if this helps or if the issue persist.