Occasional spawning with full health

Today while I fought the Twins with my friends, I noticed that sometimes when I re-spawn, I don't get 100 health points like usually, but my health is instantly 400hp full even without visiting a nurse. I'm not aware of any item that would allow this. It happened approximately 1 of 3 times I died.

I include a screenshot of my current inventory/accessories from the time, when it happened. Is this a bug?

EDIT

I've got my suspect no.1, it's the mana flower I use. It was crafted from a nature's gift which used to have this ability before 1.0.6.

I would assume that The Twins sometimes cause explosive damage. If you are killed by explosives, you respawn with full health.

Also, if you had PvP enabled, that will occasionally spawn you with full health because being KO'd by another human player causes you to not drop coins and spawn with max HP. If you play with a friend this can become an easier way to survive bosses.