"Critical error: Tag.Size == Loaded" prevents cooking and builds

Hello, first post here on the forum! :slightly_smiling_face:

I’m working in a large student project and are right now trying to make a build, solving some problems and finding others… As usual :wink:

The latest progress is that I’m able to remove buggy files and fix all build issues except this last one. So I am asking for more eyes and minds to try and fix this. Any help would be appreciated! :slightly_smiling_face:
Before posting this I searched for “Tag.Size” in the server, but found that both previous post didn’t get any reply. So I don’t feel so lucky with getting a response on this one… :confused:
But might get lucky anyway! :slightly_smiling_face:

We are using UE 5 - EA2.

This is the error code:

PackagingResults: Error: === Critical error: ===
PackagingResults: Error: Assertion failed: Tag.Size == Loaded [File:D:/build/++UE5/Sync/Engine/Source/Runtime/CoreUObject/Private/UObject/Class.cpp] [Line: 1499]