One thing that worked for me for sticking sections was putting an ice pack around the ferrule that is stuck for about 15 minutes, then it came apart relatively easily.

I have used ferrule wax specifically (it is probably just paraffin, bought it at FeatherCraft in St. Louis) and it works wonders! It doesn't make the ferrules sticky nor slippery, it fills in the little gaps between the two parts of the rod so that when you cast it it won't wiggle. When rods come apart while casting it's due to the repeated casting cause the rod sections to wiggle slightly back and forth almost imperceptibly until suddenly it will wiggle itself right off the rod with one strong cast.

Try cleaning out the ferrules and ends of your rod really well and then rub a little solid paraffin on the ends, you just need a thin layer, like the wax of an apple. Just see if it makes a difference and either way, let us know. Or, try it on a non-fly rod first. I tried it first with a cheap Shakespeare and I stopped casting my rod tip along with my bait!

Good luck!