Problem with client packages

Hello!

I have a client and all their packages come with a "hidden" TM.
It opens normally and the client says that their TM was updated properly when they receive the return package, but the TM won't appear for me when I import the package.
Does anyone know what is happening? The client itself doesn't know why that happens. I've tried reinstalling Trados, updating, changing the OS version (Win10 and Win11) and even tried on another computer, but nothing solves the problem.

Can someone help me?

Thank you