Resolved by DM Erebus' magic touch!!!
Name: Dietlinde Laenna
Where: Everywhere on the server
When: On multiple occasions, throughout the last 3 weeks.
What: After my character got married I wanted to change her name to Dietlinde Barnet. Asked for the rename from a DM, the DM renamed her and I got the usual message about relogging. After relog, the name is the same as before.
Recreate: Have tried with multiple DMs throughout different days to have her renamed but it doesn't take.
Ideas: 2 ideas;
1. New name contains the same first name and somehow that is bad?
2. During the IC wedding I made a disguise just to give her the surname after the vows were exchanged. So the first time I asked of a DM to rename her, there was a disguise of that name present in the list of disguises.