Event ID modified when passing from Web GTM container to Server GTM

We have set up deduplication with two containers and two servers (1 for EU and another for global, which we call “com”).

I used this guide (How to set up Facebook event deduplication in GTM - Stape).

Event IDs set up on both EU and COM container, but for some reason the COM container modifies part of the event ID, so it’s not matching with the web container version.

As far as I can see the set up is exactly the same, but does anyone know what would cause part of a event_id to change when passing from a web container to a server container?

Usually, this happens when you use Tag Sequencing inside the web container.
In this case, the event id changes before sending.