App erroring when logged into Gmail

[Scott_Nesbitt]

I have an app that works fine for me and one user, but fails in certain conditions for a second user.

The main table has a key like this:

When the user is in incognito mode, or clears his cache and only logs into the app, it works fine. But if he first logs into Gmail, then opens the app, he gets this error:

Any idea why being logged into Gmail affects the app?  (Yes, this is repeatable in his account, but nowhere else.)

Thanks