I'm not sure what it is with your MBP but my Firefox does the same thing anytime I open a phys.org page -- one Firefox at work using Ubuntu 16.04 and the other

I'm not sure what it is with your MBP but my Firefox does the same thing anytime I open a phys.org page -- one Firefox at work using Ubuntu 16.04 and the other at home using Windows 7 both exhibit it. Edit: Actually I just checked and the Windows 7 machine doesn't do it any more. I'm not sure if maybe a Firefox update fixed that here. I'll double check at work tomorrow too