Bad tracks count in playlist overview

Steps to reproduce

What happens?

When clicking on Playlist the modal indicate a bad number of tracks:

Here there is 20 for playlist "My favorite Queen songs", while in the playlist page, the number of song is correct (10)

What is expected?

On the playlist overview the number should be 10.

Context

Funkwhale version(s) affected: 0.17

Note: Each time I add 1 track the track counter is incremented by 2.