I appreciate the detailed description above. We have had the same experience. Periodically we would get this issue with students as a one-off. We would follow the instructions to essentialy reset the authentication both in Google and in Canvas (disconnecting the app...etc. in Google -- deleting the LTI in user account settings in Canvas...clearing cache...etc.). This time around, nothing fixes it, And it's getting worse and spreading.
We have 1600 students using Canvas. This is occurring with about 10% of our students. There is no pattern It occurs witht he Cloud 1.3 Assignment submission type and also the Google icon in the RI can identify to what causes it. I am attaching Canvas' instructions for fixing it. Perhaps that will work for some people. I
t began happening for us on 12/20/24 when I first created a ticket and escalated. It occurs with the Google Cloud 1.3 Assignment External Tool Submission Type and also the Google Icon Embed using the Rich Content Editor. I don't have any contact person at Google to work through them. Canvas has been helpful but essentially they point to Google. Could removing and resetting the integration for the entire instance possibly fix this? This has created major disruptions for teachers.
Current workarounds are as follows:
1. Use text entry or student annotation submission type (or file upload).
2. Keep the assignment paste in a share link from Google drive outside of Canvas. Make sure it's set to public or organizational, and paste in the assignment description. If needed, the student can submit their response in the assignment comments area of they aren't able to use SUBMIT.
3. Upload files directly rather than using a cloud embed. This way they live there forever and we don't need to worry about sharing. Of course, this takes away the functionality you get with the cloud assignment.