[Plugin: Media Library Categories] Slugs aren't checked

I’ve just noticed it’s quite big problem.
When I change slug of media, for instance ‘hydra’ to ‘hydra-media’ my category of posts it ‘hydra-media’!

I checked in DB. In ‘terms’ table there aren’t two ‘hydra’ ‘categories’. It means the plugin overwrote my categories.

I’m thinking about categories children. What could have been changed?

Have anyone an idea how to fix it?
When I change or delete post category or media category the second one is changed or deleted as well.