The Sport of Kings - Failed to return horse?

[Code Panda]

After winning the Talmberg Horse Race and returning it to Zora, the quest is completed but the (optional)Bring Zora's horse back objective has failed. Quest log shows it was returned oddly enough.

I've reproduced this 6 times now right, saving the game before getting on the dappled grey. Every damn time, "Failed".

[Code Panda]

https://steamuserimages-a.akamaihd.net/ugc/954095427581819951/5F2CA0D0D249E57505585C32ECB2E96CB7B80C0B/