Packaging: Malformed Tag

Hello

It looks like to the scant other posts I have been able to find online that this error has shown up in previous versions of ue4. However there is very little information on what it is.

For context: This is a 4.26 project converted into UE5 EA.
This shows up when trying to package the game for windows on a Development Config.

What is it and how can I fix this?
Thanks

This is also happening on 5.1 .

Trying to package any project fails on linux . It was working fine on 5.03 , but 5.1 fails by raising all assets as “malformed tag” .
Packaging on Windows works fine , that is only a linux issue (Not tested on mac ).