I have 5 cuttings who have gone limp on me. 

These are all 2-3 node cuttings in the root riot set up. Out of the 50 or so cuttings going, 5 limp noodles isn't a bad ratio but I was wondering why they have gone limp. Of the 5 cuttings that have gone limp, they make up 4 varieties. The cuttings all around them are doing great.

They do have T5 grow lights, and stay at around 70-73 degrees. They are spritzed and aired daily. Their little cubes are moist.  I did see leaves before I saw roots.

Are these guys just spent from putting out leaves and used up their reserves? 

I hesitate to do anything real different because the other 45 seem happy. Lots of roots, lots of leaves. I'm not throwing in the towel on these 5. They look promising below the rooting cubes. Anything I can do special for these guys?

Nichole, I'd try putting a cup with a small hole over them. I noticed on mine, I tie a plastic bag over the tip, so the leaves stay moist by not the cup, even a zip lock bag works at this point, cut the dead leaves and put the tip in a bag, you will see new growth...these creatures are so sensitive, even holding them can 'tell' them to go on whimping mode.  I am faithful it it just a phase and will be fine. I have a couple that went whimp on me several times and are still hanging in there...don't give up.

They have the plastic dome already - I keep them covered nearly all day and air them out for a few minutes in the evening.

Yeap,
I also bet that the main twig (somehow) got rooten-down-under breaking the 'water-plumbing' link to the top...

if the bottom of the cutting rotted, you can cut off all the bad areas and start all over.. I did with a few and even rescued a few for bud graft.

I've been potting up to a cup as soon as I see roots coming out of the root riot cube.  I have noticed in my tray that some cubes stay a little more moist than I would like while others dry out faster.  So I figured why not transfer to cups where I can control the moisture more easily...though it is never easy! :)

Bottom of the cutting is most likely rotted.  Cut it off to just below a good node and start again.  My experience is that you will not be able to save this rooting but if the cutting is still good above the cube, just start over.

Wow, look at all those cuttings in the background!

You guys were right. There were lots of root initials but they had gone bad and they were rotted below the cube surface. There was only one I felt had a prayer. I pruned it back and put it back. I tossed the rest.