Just a heads up - we have run in to an issue with Google Drive Collaborations that use the Google Drive (via the Google Apps LTI) option, as seen here (specifically, not this one).
User A creates a new collaboration. They share it with User B within the Collaboration settings in Canvas. The collaboration is created, and User A sees the link and can access the document. The sharing button for the Google Doc is unavailable.
User B sees the link in Collaborations, but when clicking on it they are told they need to request access (a Google Drive error).
The document is not actually shared with anyone.
Turns out the Collaboration tool is showing that the doc is shared, but those doc sharing settings are in fact not being pushed over to Google; if User A mouses over the share button in the doc, the hovertext will display as 'Private Only To Me'.
Currently our only workaround is to have the doc owner (User A) open the doc directly in Google Drive such that the sharing settings are not greyed out (as they would be if opening via Canvas), and add the other users. Having the other users click the request access link in the error message helps since that sends emails with a link that pre-fills the sharing settings, and also opens it directly in Google Drive.
We've tested and confirmed this behavior at this time, and have an open case with Instructure Support. I'll update when I have more.
EDIT: Further testing shows us that it is sporadic in nature. For example, if we add two users to the same collaboration at the same time, user 1 may successfully be added to the sharing settings whereas user 2 may not. Doing the same on a second document may have no issue.
We've experienced this as well and also find it to be sporadic which has made it difficult for Canvas support to replicate.
I know this is from last February, but are you still having these issues? I am currently experiencing something similar and the inconsistency amongst errors and users has made troubleshooting difficult here too. Hoping maybe you discovered a resolution?
We still have the issues sporadically.