Print dialog in KDE Plasma are not fully translated:
Probably an issue with the translations of KDE Plasma itself and not Solus if I'd guess...
Can you run a check and see if packages are broken? The translation are correct for me
No broken package on my system.
I also checked on another system and I have the same problem (with an HP printer so I don't think it's related to the driver).
I made a fullstack upgrade for kde, can you check after the stable sync if this still happens?
Upgraded (from unstable) and no change. BTW, here's my language settings: