Ive had a few plants grow a leaf that didnt quite open as it emerged from crown. All of mine could be gently forced open. Hard to tell in this picture, but is it totally sealed? If so that is indeed strange.
Don't cut... It is possible that the plant may put out a spike in the middle of that "cone", indicating that the growth is at an end ("terminal" spike). That doesn't mean that the plant is "terminal" by any means, it may be preparing to send out new growths from the base of the plant - which in turn will eventually bloom so that you get twice the number of flowers! Let it do its natural thing.
more light will keep the leaves strong....when the leaves get long instead of sturdy, they are weak, and flop around.....I would not be happy with that plant....