I think, it is a dangerous sign, if Heliamphora get 'umbrellas'. It is a sign
that they don' t have enough light and maybe that they are grown to warm.
In my greenhouse they do it sometimes in spring (January, February), when
there is just few sun in Germany and in this stage they are quite a good
prey for fungi. So, keep cool :-).
In nature they do it just in very shady places sometimes.
Joe