Storage Pool is full when it's not?

I don't get it what's going on. You can see that upwards it shows as full capacity and then storage capacity has a lot of free space. Any idea what's going on?

I don't have any raid configuration. Every drive basically acts as it's on volume and storage pool.

Last thing I did before I got this is added an external USB drive. Maybe because i added a second library folder on Plex point int on the usb, DSM gets confused somehow?