Do you know if the users are actually trying to click the button? I was trying to replicate that but could not. I have a feeling the users simply don't know there is an additional tab, they would need to hover over the tab titles in order to know there is another hidden tab, maybe that happens as they change their screen size. There is an additional tab at the right side in the below, but a user would never know that until hovering the tab titles.
Yes, the users are trying to click the button. I didn't show it but there are instructions above the tabs to let them know to hover over the tabs to reveal the orange button to see more information.
