Nope, this is intended. Boss saddles are expensive to make, and at the same time, they are used to instantly tame bosses. So to prevent easy boss taming, the saddles are permanent (just like Titans) in order to prevent people from just taming every bosses they could find.

However, there is a "cheat" where you can get the saddle back without having to kill the boss. You can upload the boss to a pylon/obelisk, which will forcefully drop the saddle...it's unintended, but there's no fix unless the creator decides to block them from being able to be uploaded.

Awesome thankyou

if you upload your dino at the obelisk to take it to another map the saddle comes off, then redpwnload the dino, (work around) check server allows crossmap uploads/downloads as there is a chance of losing it, but you get the saddle back.

Now how do i unsubscribe :D

Yeah, that's why most servers disable uploading and downloading as it allows players to literally upload a dino from single player and downloaded on someone else's server. It's a major cheat lol. But it's not an issue if it's single player.

Hm, maybe Psycho reads this, and it would be possible in the future to upgrade the saddles by lay all materials in the boss' inventory and push a button - without removing the saddle from it's back. Sure, the "cheat" stays, but i think it could be a way instead of crafting new saddles and taming new bosses on Servers without upload option...

A way around this I found is if you have the Dino Storage mod you can store the boss and it will take off the saddle. Then you can unstore the Boss and put the better one on.