I'll check again tonight but i'm positive i've seen them drop everytime i switch from cat to normal form to heal.
Feel free to check it and tell me if i'm stupid but i've noticed it a couple of time with RIP should be 12 seconds and it drops way faster.
I'll remove the thread if it turns out they actually drop due to the 12 seconds expiring ( i don't have a timer addon on so yeah u might be right ).