I have a couple of thoughts, but can't say for sure without a picture that shows the flowers better. Can you get a close-up of the flowers?
The species is P. gloriosum, although I have had it happen on occasion to other species. The conditions are probably fairly dry, as it is...
Occasionally one of my philodendrons will have a problem with the leaf not developing and unfurling quickly enough, and the petiole ends up...
