Thanks for testing all, it definitely gave a fresh perspective!
VMware were able to replicate the issue in our environment, they produced a mountain of logs, but weren’t able to provide anymore insight than that.
We weren’t able to reproduce the issue in other AirWatch environments. However, we were able to reproduce in our production environment, in test OGs, with the same Wallpaper, with and without DEP.
But we were able to remedy the issue in our test environments with a smaller version of the Wallpaper image size.
So it seems this issue was a combination between iOS 12.2, our AirWatch environment, and the wallpaper image file. (For reasons unknown to me) The original Wallpaper seems to be over 5 times the size it needs to be, which caused the issue. However, has never caused an issue with any iOS version in the past 5 years (including iOS 12.1.14), except for iOS 12.2.
I’m looking to change the Wallpaper to the smaller image file tomorrow in production, so fingers crossed, this resolves things once and for all. I’ll update with the final outcome, and thanks again for all the input!