I think you should be carefully with your Heliamphora.
You should give them more light and maybe cooler conditions (10-
20 degree C. You can find it also in nature, when Heliamphora is
growing at quite shady places, that they get thin pitchers and
large 'umbrellas'.
I get the problem sometimes in winter in my greenhouse, when light
is to scarce. That is the time, when they are most endangered,
because fungi will get good luck to kill them.
(P.S. German winters are oftenly without much sunshine :( )