Maybe you're securing them too tightly to whatever you're securing them to. OR, are the growth tips pointing down? What are you using to secure them, it can't be tight or injures the growing vine & kills it.

I make sure the growing tip is upright and I've been securing them with dragonfly clips. They are held nicely in place so maybe they are too tight. At this point should I just leave the vine alone or should I snip it off where it seems to have dried out?

Die back can happen on certain hoyas with the growing tip pinned in the downward position like Imontestella stated.I have had vines die back almost 8 inches from this sometimes.If there is a few inches of the vine tip free,some hoyas will sent the tip back growing upright.Not enough water can also cause the vine to die back.I cut off all the dead vine,but just make sure its totally dead or you may get some sap drippings.

Thanks Jimmy. It's been happening on my Carnosas. I'll go ahead and trim off the dead vine.

Also check the leaves to see if they feel leathery or look dehydrated.Another sign of under watering.Some of my larger carnosas are rood bound and I have to dip the whole pot in a bucket of water so all of the roots get wet.You may just have some dry spots in the pot that the water wont reach from top watering.Just don't over do it...lol