I can't dismount from a tamed mob when I enter Rose Garden while riding it. I have tried pressing ride monster skill, right-clicking the riding icon on the top right corner, and unequipping my ride, and none of these work. As a result, I had to close the game and restart the client to get it back working.
From what I've seen you're lagging. When the mobs attacked you, your HP bar didn't move an INCH. Even when you're auto healed the hp bar has a reaction. Did you try writing in chat to make sure you're not lagging? Cause this happened to me when I was lagging.
I suspected it was lagging as well. Typed in chat and the message was sent through. You can also see there were messages in the chat window popping up. The hp bar did behave weird, but when hitten by mobs, the potions were consumed (In the case of real lagging, potions won't be consumed and you will become a small tomb when you are back)