Unable to add to library, sometimes

Roon Core Machine

Mac mini 2018, Core i7, 32Gb, Ventura 13.2.1

Networking Gear & Setup Details

Connected via utp 1Gbps to UniFi UDM-Pro, no vpn

Connected Audio Devices

Sonos: Arc, One, Sub, Bookshelf, Table Lamp, Roam
AirPlay: HomePod mini
Direct: MacBook Pro, iPhone, iPad

Number of Tracks in Library

20,000 tracks

Description of Issue

Noticed that sometimes I can’t add a song/album to the library, other songs work. This is not about background indexing as I’ve read in other threads. There is no spinner, just Add to library disabled without any clue.