Duplicate (triplicate, etc.) paragraph styles

Hi everyone! I just imported some master pages into a new project. After that, while tweaking some paragraph styles I noticed a weird thing: all the custom paragraph styles that came with the imported master pages were duplicated, triplicated… there were even 12 copies of the same paragraph style! Some of them I could delete, but others I couldn’t (the option was greyed out). I assumed it was because they were in use. This shouldn’t behave this way. I have to manually find every single instance where each copied paragraph style is used and change it to a single one and then manually delete every duplicate.
Am I doing something wrong or is this a bug?

This has already been reported and I don’t think it is the expected behavior…

Thanks Marc for the information!

Yes, this is on my list of things to take a look at in due course.