Distribution List Delegates disappear randomly

Question

I have started having a weird issue in which in one particular Distribution List the delegates are randomly having their send as status revoked. We only find out about it when they go to send an email as that particular distribution list and the email bounces back stating that they are not allowed to send as that particular address. I found the problem stated here in 2023 https://learn.microsoft.com/en-us/answers/questions/1180182/distribution-list-delegates-randomly-being-removed

The issue is exactly the same in that if we re-add the user via the EAC some of the time the changes stick whereas other times they disappear after a few hours. It seems that if we make the change using the PowerShell command as stated in the link above the change sticks.

Has anyone else encountered this problem more recently in 2025 and if so what did you do to fix it?

Answer 1

Barring an issue on the UI side of things, there's also the possibility that some automated process is removing said permissions. Have you checked the audit log to confirm no changes are being made, other than the ones you intended? https://learn.microsoft.com/en-us/purview/audit-search