Corrupted segmentation masks in UE5.2 first person map

[4ndr3aR]

Hey there,

pardon me for keep opening issues on probably trivial problems to solve, but this one is really defying my debugging abilities.

The problem is: if I use your CameraCaptureToDisk example (without plugin, I can't find a way to compile it), I can capture RGB images and semantic segmentation masks without any problem.

Conversely, if I create a new project (always without plugin) using the first person template and map, and I try to repeat all the steps:

1. copy CameraCaptureManager.h/.cpp from the plugin to Prjname/Source/Prjname,
2. add the dependencies to Prjname.Build.cs to avoid linking errors,
3. copy CameraCaptureManager_BP.uasset to Content/CameraCaptureToDisk/Blueprints and PP_Segmentation.uasset to Content,
4. build+cook+run
5. open the project and add the two CameraCaptureManager objects and the two SceneCapture2D objects (children of a CameraActor object for convenience),
6. have the two CameraCaptureManagers use the respective SceneCapture2D objects and, only for that concerning the segmentation masks, tick the PNG flag and add PP_Segmentation as postprocess material,
7. edit the level blueprint and make the capture pipeline activate by pressing a key on the keyboard,

I can still capture RGB images but I capture corrupt semantic segmentation masks.

I've tried every possible fix/workaround that came to my mind, the first of which was obviously disabling the alpha channel fix that I proposed in the pull request (it seems to be irrelevant in this sense, it works fine on both CameraCaptureToDisk and my project). What am I doing wrong? Sounds like an alignment issue. The image seems to be there but it's badly aligned, do I see correctly?