The grey arrow means "Sketch with a problem".
See the following Solid Edge help page for more on PathFinder icons:
As Dave points out, there are geometry errors....this will usually occur when a dimension or a relationship nolonger has, or has lost, reference to that entitiy.
The real question is how do you go about debugging the problem when the geometry shows black (fully constrained) yet still broken?
In that case, I'd be looking at the plane the geometry was created on.....it's location & orientation is subject to the same edge/face locate errors, if they change/diasappear.
Sean, yea that can be it but it would be nice to know what is broken, the program knows its broken so why doesn't it just say so? Immagine writing a document in word only to have it tell you that there are spelling and grammer issues but not pointing out where they are...
From the help documentation link I sent you originally:
"Feature with a problem (select the feature in PathFinder and see the PromptBar for details)"
So when I select a sick sketch feature in my PromptBar it (and pop up tool tip) is telling me what is wrong with the feature. Are you not seeing this behaviour?
Try as I might I can't find an SE definition for the term "sick". Do you starve or feed a sick feature?
For those who wear their caps on backwards they may be forgiven for thinking that Solid Edge is actually paying them a compliment for creating such a cool feature. "That reference plane is really sick, man!"