Someone stole the portrait of our baby girl harpy from the great hall?! It was TAKEN! Well... the Champ has a unique set of skills, and if it isn't returned...
Oh, did you mean the bust of her isn't showing up in scenes where she's riding Daliza or with Zhara?
Are you sure you don't have her set as the back portrait in the bust window? If there's two or more busts, you can place whichever you want in foreground. Usually the back one is larger for visibility, but Mitra is tiny, so maybe she's hidden behind Zhara or Daliza?
If not, that is weird.