Hi,
This is not an expected behavior, when I open a custom preference center, I can click on the Edit button to edit it:
so, I suggest you try the following first:
1.Turn on the feature switch
2.Find the Compliance profile page in the app designer, in the settings tab there are three available tables, try toggling it to find the editable one.
3.Try clearing your cache and creating a new preference center using privacy mode to see if you can edit it.
If none of the above steps work, please raise a support ticket to give Microsoft feedback on this issue:
If my answer was helpful, please click Like, and if it solved your problem, please mark it as verified to help other community members find more.
Please feel free to contact me if you have any further questions.
Regards,
Haig