I know that people often refer to this Oberteig as "flour", but it is mostly proteins, polyphenols, beta glucans, lipids and the like that have precipitated out during the mash. Essentially this is your mash break, which is probably a sign of good pH and calcium concentration.
The risk to channeling is probably that it can lead to flow around the outside of the grain bed having less resistance than through the grain bed. That could lead to reduced efficiency and over sparging during a fly sparge.
I've cut it before, but always followed that with a second Vorlauf. A good quantity of whole husks should prevent this from being a problem, though, for most mashes.