White Screen for Pages Only When Adding or Editing

So, here is an odd problem to have. After several days of troubleshooting, OneSignal is breaking my backend with a white screen of death. But it only happens when adding or editing Pages, not Posts. After disabling OneSignal, everything works fine.

I’ve tried enabling the plugin by itself with no other plugins running (testing for conflicts), and it still borks the Pages section of WordPress. This only started happening after the update from a couple of days ago.

This is happening across all websites I’ve installed OneSignal on, and not all of them use the same plugins and such.

Any ideas?