Yeah, so I know this is probably one big fat annoying coincidence, and I don't want to give any hope of anything, but I noticed a pattern form for me while doing AMAN Trove today on different characters.
So the way I do this, I open the front left chest, the back left, the one next to that, the chest in front, the one next to that, and so on. Once I get to 6 I seriously consider opening the gold, because most of the time the 7th is Chest-o-Plenty. The way you open them shouldn't matter, so long as it's the same way every time across all characters.
Today, I did a short spell of four Mars Orbs, two on each character. The first was on my mule in Waughroon Shrine. So I opened the front left and got Noise, the second was Chest-o-Plenty. The second I got Thud on first, and Loud Thud on second, and opened the Gold to get a Dagon Breastplate (mule has it now despite no Omen access.. woo).
Ok cool, I got lucky. I switched over to my main character and went to Balga's Dais for a change of pace. Guess what happened? Exactly the same result. I got Noise and Mimic on first pop. Thud and Loud Thud on second pop. Got a body piece, but sadly it wasn't an Omen body, but the rare Enforcer's Harness (maybe because I already have Dagon?). What's the chance of that happening? To get the exact same result across two different characters in two different zones? It's either a crazy coincidence, or there's a pattern.
I think I'm going to start making a record, because if there are any kind of presets at work, it may be possible to figure out where things are based off earlier runs. It's also likely this would reset per game day, real day or week at JP midnight, so if there's any recording over several characters you would want to do them quickly back to back and possibly in different areas. Again, it's probably more likely that I got stupid lucky to get the exact same result like this, but what if it isn't? Just a thought.