I’ve updated the plugin to the 0.5.0 mobile SDK.
https://github.com/EpicGames/UnrealEngine/commit/010b67402085fbef8a0e77c7e37834b7366421de
https://github.com/EpicGames/UnrealEngine/commit/7e8d7ed115ff3c63701cda1fcd0f3d15eaa7263a
And then fixed the back button global menu support in the following commit. Note that the global menu fix is dependent on the 0.5.0 integration.
https://github.com/EpicGames/UnrealEngine/commit/1c0dd94397c9c4a92f2aa2e7c9da8e0126dd5393