Cattleya Evolution

[Phyrex]

Hi all,

Sorry for the somewhat confusing title, I just didn't know what to call it. I've recently purchased my first cattleyas and one of them had its spike cut to just above the sheath be the store. Now the spike is completely black and the blackening is moving all the way in the sheath; as far as I can tell all the way until the leaf. The sheath has started to yellow from the bottom up. The part where the sheath, leaf and spike meet in the crown of the leaf seems to be a bit fluffy (inside the sheath).

Is this the normal way for cattleyas to get rid of the sheath, and if so should I help it or prepare it in any way? Btw there is no new p-bulb growing yet.

Thanks.