I encountered a problem, where occlusion doesn't work for the area target and its children objects, only on Android build (haven't tested iOS).
Occlusion works just fine in the simulator mode in Unity and there doesn't seem to be any problem.
To make it clear, I added occlusion mesh in the Editor (AreaTarget game object options) and haven't done anything extra (which worked in Vuforia 9.7.5 and Unity 2019.3f4)
Some additional information:
Unity version 2020.31f1
Android, Galaxy S20 FE
Only one area target object, imported from Area Target Creator tool and Matterport API.
I solved this problem by adding the NavMesh,prefab to the scene and applying the occlusion shader to its material but I am not sure if it is a good solution. I am now having this same issue on a new project, so was wondering if this is a known bug or I am missing something very obvious.
Sorry, if this is the wrong place to post. Thanks in advance!
Edit: My area targets are new and compatible with 9.7+ and I am not getting a waring in the Unity editor. Also, I just saw the manual occlusion mesh guide in the Vuforia release notes, will try that anyways.
Edit 2: ATG Windows app I was using was 9.7.5, while my Vuforia version in Unity is 9.8.5. There wasn't an incompatibility warning message though.