Using Arcore 4.19 build from source
link:https://github.com/google-ar-unreal/UnrealEngine
create a blank Blueprint project
create a GoogleArcoreSession and AugmentedImage data assets
initialize the ARcoreSession in Blueprint
This is 2 month old issue and its still not been fixed. Issue has been fixed on source version of plugin. Please update the plugin in the next point release.
Even their sample project, the one that puts picture frames around pictures crashes the moment you try to enter AR mode. Something about trying to access Array slot 0 in 0 size array, then shuts off.
Using 4.20.2 and arcore 1.2.1
From what I found the array of pictures stored is being returned as 0 elements. The blueprint should check first before attempting to access any elements from it…thats why it crashes.