Barry, thanks for looking into this! I wish I had taken screenshots yesterday because the behavior was very different, but I am seeing the same thing you are describing now.
My onAuthorized callback fetches the user’s display name using their token and shows/hides the button according to their linked state. It relies on onAuthorized firing every time the panel loads. This seems like an incorrect assumption now, but it worked as expected on desktop so I didn’t notice this problem until testing mobile.
I will change my assumption and see if it resolves the issue. Thanks for your help! I’ll post my result here.