Sanby that is not normal PS behaviour -- for ANY version.
There's simply something specific that you're doing that's bringing on this 'specific' type of behaviour from PS.
Can you run through in a bit more detail what it is you're doing?
Bear in mind that PS acts in specific ways according to some basic guidelines, where colour & attributes are concerned.
If you save your PSD document while in RGB mode, then it gets saved in that mode, and will always re-open in that mode. If you're in INDEXED COLOR mode when saving, then the same rule applies. And this applies to any specific colour mode. But this does NOT apply to saving an image in a generic graphics format like Bmp or Gif or Jpg. This only applies to PSD files --
Photoshop specific format.
One of the specific situations where PS will react unusually is when, for instance, you copy-n-paste a bitmap image into your current document. The next time you go to create a New Document, PS will still have loaded the colour mode and dimensions of the image you pasted previously. So you'll need to watch out for this every time you go to create a New Document.
I myself see this as a flaw, but i'm sure Adobe must've had a reason for making PS do this. It just never serves my purposes is all. But it IS something about PS that people need to learn. And there are other small "quirks" like this that people will learn over time, just from using the program.
Mistakes will be made, and revalations will be had.
It's the way of the world.
saving as a .jpg 
Linear Mode
