There was no clarity. Bungie.net > Patch 2.4.1 notes > Declares clearly with no way to misinterpret that you can get your Horns from the Kiosk. PlanetDestiny told me I could do that after going through the notes. MoreConsole told me I can do that after going through the notes. I dismantle my horns. I go to Kiosk. No horns. I complain on Forums. Bungie employee redirects me to a -blam!-ing tweet that stats it won't be available until FotL. I have lost my horns. Forever.

I saw no wording that implied the horns kiosk will be available when the festival starts. I did see wording that said the horns would be available as of 2.4.1 patch. Ugh....I take that back as there is a Twitter post (not in the actual patch notes that I remember). The kiosk which is now there for horns (did not exist prior to 2.4.1) clearly shows only a portion of the horns I have. So....2.4.1 patch made a kiosk to hold horns but its broken until the Festival starts...?? LOL. Its a bug...simple as that. If we are LUCKY they will patch it when the Festival arrives but it is not a 'feature' to be implemented when the Festival starts. Nit picking but getting tired of the continuous and numerous actual bugs in this game that people try to dismiss. Edit: Clarity

I'm having the same issue. I have a duck horn, electric horn, and fog horn (all legendary) in my characters' inventories but they do not appear in the kiosk.

I have the same issue. It would appear the 'patch' isn't retro-active. Maybe put it in your vault and see if the kiosk updates after that.