I give some more details.
1st case) A. kiusianus - plant not even developed the leaf correctly,
never unfolded completely and died fast away. The tuber tripples it's size.
2nd case) Helicodiceros muscivorus - i planted several tubers (some very
tiny) in a pot, just one realy thrived. Meanwhile the leaf begin to die
back and I digged down to see what the tuber do. And found beneath the
biggest tuber (the one with leaf) another tuber even bigger than the
other ever was.