Protected Prefix anomaly
I have some presets with the s- prefix. When I protect them it picks up some presets that contain the characters but not as a prefix as below:

This is not what I expected or want.
I had the same problem. I now use a longer prefix for my presets ("psst-"), that is not included with other names.
I agree that the cleanup should only check the start of the prefix, and not include "...radius-.."