Yep.. Talked with John Monsen in Sage tech support. I have a case open and he declared it a ""product defect"", wrote it up, and sent it to engineering. My bet is this isn't considered a critical issue so a hot fix won't be delivered. However, since it is associated with a new 2016 feature that isn't working properly they may put the fix in the next PU or version release.
The default settings stick from session to session.. as designed. Of course, the SO setup option is universal. The default SO option is by user.. and seems to be working by user. The issue is that when the SO option is set to increment the quote expire date by a given interval, it doesn't work if the quote is set as the default order type.