[horde] Does the ActiveSync change the UID of events during sync?

[Sebastian Arcus]

Horde 5.2.23 + Kronolith + ActiveSync

I am using Thunderbird + TBSync to sync calendar items to the Horde 
back-end. When a new calendar event is created, Thunderbird assigns a 
UID of format:

823ba2e7-de3c-4ffc-b2d2-8303fb589b81.

After the next TBSync sync run, the UID is changed to something like:

20250919125755.GNZD0XKVS4MXYE5RerGsXXM at mail.mydomain.com

I am trying to figure out if TBSync changes the UID, or the 
Horde/ActiveSync back-end. Would anyone know?

Side-note: this breaks event invites both when Thunderbird + TBSync + 
Horde is used at the received or at the sending end. The sending end 
sends email event updates with a different UID from the initial invite - 
so the receiving end creates a new event, instead of updating the 
original one. And when the receiving end uses TB+Horde install, the UID 
is changed after accepting the initial invitation, so any further 
updates to the event received over email, again, create a new event 
instead of updating the original. Also, event cancellations are not 
processed properly because of this.

Any info would be much appreciated. Many thanks