In-browser interactive button hit state is wrong but browser zoom is correct

Anyone know of another way this could be broken? It's literally just a green default library "play" button, but the one guy who has to sign off on the project has a browser that's hozed in some way such that he can barely click that button.

Usually, this is caused by the zoom of the browser window having been changed, but not this time apparently, so I'm trying to find out if anyone else knows other ways interactive buttons can get their hit states out of whack.

Thanks in advance!

Eric.