[David Cutler]

Interesting question Vince. I’m relatively new to layers so I can’t say that I’ve come across this problem myself.

How are you combining the drawings? Have you tried a simple copy/paste pages to see if that brings the layers over without corrupting them? Just a guess but if you are using a more advanced combining method there may be some sort of setting that is flattening the layers out on you.

Curious to see what others have to say on this.

Dave