Yep it definitely does happen - it is equipment with moving parts. Be sure you check and tighten nuts as needed after each hunt. Now here is what I have found that helps.
First, many that are building these platforms are not doing any prep work to the seats. Take a close look at the part of the seat that goes up against the aluminum stock. IT IS NOT FLAT folks - it is cast aluminum. You HAVE to get a file and file that down flat so there is EVEN pressure against the aluminum stock. To me this is the single biggest noise producer and most that have made these seats failed to do this as I outlined in my original mod.
Second: fill that tube to keep it from flexing at that spot and the spot where the bolt comes in contact. I personally like bondo, fiberglass resign and chopped fiberglass to do this. I have also used 2 part epoxy compound with chopped fiberglass matt. What ever you use the goal is to stop the tube flexing.
Third: use big washer and nylon washers at the connect point. Alternate them so there is not metal to metal contact.
Fourth: use silencing material where the bolt contacts the tube. I like a heavy rubber glued over the tube at this location. Something the bolt head does not easily penetrate.
Last: you have to be mindful of moving pressure from side to side. I usually try to keep most of my pressure evenly across the platform. If you have to stand on one side for a shot then realize there could be noise and try to do it before the buck is right on you or - apply pressure slowly.
even with all these you have to understand the metal contracts and expands with temps so at any point there is always a potential for a bit of noise at moving part junctions. However, I have never spooked a buck with any of my various mods and they sure as heck are quieter and more stable then the strap on steps I used for years. Even my helium sticks will sometimes make a bit of noise when I stand on them depending on how hard the bark it. The softer the bark the better they bite and thus make less noise as pressure is applied and taken off them when I stand on them to hunt.
Yep it takes a little extra effort to get these things tweaked just right but it is worth the effort.