In the panel I sent flanmalth still very much had his body, the only thing Natsu did was hit him with a large rock as magic wouldn't work on him. Flanmalth then says his lines and evaporates, that doesn't happen when you hit someone with a rock. He literally willed himself to die and referred to the entire guild as being unable to die, its literally a respawn point as he says.
I don't care what the wiki says, literally a
few panels later he pops up in the pod just before the lab is destroyed and killed again, so no he didn't teleport and has never shown to be able to teleport