I've been investigating this oddity, and I think that it comes from using configurations.
With this model, I have a process that is a walking beam type application. It has 4 basic positions. So in design I have 4 configurations plus a couple more (home, move1, move2, ect). I have the configuratiosn set so I can easily switch and check interferences, ect.
I had been working in the home config (not default) for sometime. And was actually in the home configuration when I had exported my assemblies. Well, from observation, when one saves out an assembly it saves it out in the default configuration, not the current configuration. This makes sense to me.
I rarely use configurations, so I hadn't really run into this problem. Thinking back on it, I have seen this before with another model that I used configurations.
So FYI, if you are using configurations, use default as your "default" (ie home). And be in the default config when you export your parts & assemblies. And there shouldn't be any surprises like parts mysteriously changing position & orientation.
Joel Parrish
www.pai-design.com