Patch 7.2.5 hotfix2 build 24393 was released to the PTR released on June 22, 2017. Build 24414 and 24415 were released to Live on the same day, but skipping the PTR apparently.
Blizzard acknowledged a problem with loading screens on Intel GPU on Mac OS X.
^ Rommax 2017-03-29. Load screens seem graphically glitches now :(. Official Mac Technical Support forum (US). Glitchy looking loading screens on Intel GPUs is a known issue. We're working on a fix. For the time being, it should be a benign issue. It only affects the appearance loading screens.