That's the "race condition" part...
I've had the problem in my mod where the script can fail on FASTER PC's, but works fine on slower ones. And this would explain the complete "randomness" of it... why many users never have the problem.
After you both discussed about slower and faster systems, I installed steam and skyrim on my older laptop to test it out.
My mainly used computer should be placed in the category "fast", i think (still, at least ...):
Intel Core i5-2500K 3,3 Ghz
8GB RAM
Geforce GTX 470 (slowest component)
AsRock P67 Pro 3
The Laptop I used to test your suspicion is slower, but maybe not slow enough:
Intel Pentium T4300 (2,1 Ghz, 800 Mhz FSB)
4 GB RAM
Geforce G210M
... and some creepy Acer motherboard (since I bought that Laptop I dislike acer, but that's another story ...)
After installing and patching Skyrim in Steam I activated a copy of my quest-mod. This one comes with a bsa-file. Long story short, this test resulted that I also have to save and load to see the dialogue options. As mentioned before, even the laptop could be to fast ... don't know what kind of systems you were thinking about. Actually - on the laptop - I only can run the game in medium details, but as you have seen, the graphics card is not the best so it could be relaited to that component, while the CPU loads scripts and quest related data fast enough, resepctivly to fast.
OT: Finally I thought about Emmas excuse and, as I am not a native speaker too, I should excuse my mainly or at least partly poor english too. It's a bit difficult for me to estimate the qualitiy ...