it's something i noticed this yr. whatever is on the top of the top node seems to be either drying out or starting to rot. i didn't care too much to notice before, but it's more pronounced this yr. 

typically, i want to leave at least 1" above the top node so if a new branch comes out of the top node, it won't have a weak point, but there are cuttings which are doing just fine. do you cut flush to the top node or leave some room? 

Pete, I like to leave 1/4 to 1/2 inch but sometimes cuttings arrive without any room to spare.

I cut on a diagonal pretty close to the node. As long as you do not damage the node, the limb will stay strong. Anything that dies off above it is an entry point for undesirables.

What James said.  1/8 - 1/4".  Even 1/4" is too much.  OTOH, I leave as much as possible under the node.  Anything below the node is a potential rooting spot.

About 3/16" :)

My cuts are also diagonal, which is an industry practice for propagating most things.  The lower side of the cut is opposite of the top bud and about equal in height to the bud, usually.  That is just my style, though.

I'm wrapping all of my cuttings with Parafilm (BuddyTape version).

Pete... there is NO pint to leave anything above the top node...having said that, you should know the parameters of a Node.  This is an excellent sketch that some one had posted earlier last week, so I am re posting it for you.