This issue is caused by a bug in Sketchbook version 6.0.1.
The bug affects iPhones on iOS 16.1 and higher. iPads are not affected.
Please do not delete or uninstall the app in an attempt to fix this problem - doing so will not fix the bug, and deleting the app will delete your art.
If you have any questions please reach out to our support team at firstname.lastname@example.org