Hi @MaliaWildman,
We run into similar issues at my institution, primarily with collaborations though. In most cases the cause is the students being logged in to more than one google account, and google just not handling that well (in my opinion). Our usual advice is for students running into this to log in to Canvas using a private/incognito browser window, and then log into google when prompted there. That helps ensure they are only logged into their correct google account and no others at the same time. I see this as much more of a google bug than anything Canvas/Instructure can fix, but others may see it differently.
I hope this info and the suggestion may help a little, even though I know it's not perfect.
-Chris