Hello and thank you for your reply.
1. It appears to only happen on mine, but I'm not getting around enough to see others too often
2. I believe it's when I'm even at my base, but far enough that it is out of the draw distance or view on the screen.
3. It's when I've returned to it, from being away. I've never seen them disappear in front of me when the trading station is in view.
I hope these and the screenshot help. I've also saved and revised all of the prices that I have, not sure if that affected the items or not.
1. It appears to only happen on mine, but I'm not getting around enough to see others too often
2. I believe it's when I'm even at my base, but far enough that it is out of the draw distance or view on the screen.
3. It's when I've returned to it, from being away. I've never seen them disappear in front of me when the trading station is in view.
I hope these and the screenshot help. I've also saved and revised all of the prices that I have, not sure if that affected the items or not.