Campaign missions occasionally completely lock up the app

Apologies if this has already been reported, I didn’t see anything that seemed to match.
Using a MacBook Pro Retina 15-inch Mid 2015
Processor 2.2 GHz Quad-core Intel Core i7
Memory 16 GB 1600 MHz DDR3
Graphics Intel Iris Pro 1536 MB

During some Campaign missions (seems to most often occur when a Paladin not in player control uses invulnerability) the audio continues playing but everything freezes up. I can continue clicking on things and it gives responses as expected but otherwise appears as though pause is turned on.
While frozen, none of the menus can be brought up on through the F keys. I can usually tab out as long as I have another app opened but if the Warcraft 3 client is the only app running and everything else is minimised I can’t even Command + tab to close the app and have to power cycle my mac to recover.