Impress, Export To PDF, will not Fade Smoothly

This worked a week ago, maybe two weeks ago, I think. I can’t prove it 100%, but I thought I saw it work properly.

When I choose [File], then [Export as PDF], the resulting screens will not “Fade Smoothly”.

YES: The display WILL fade smoothly using LibreOffice Impress.

NO: The display will NOT fade smoothly using Adobe Reader.

In fact, it fades in some unpredictable way, typically either an instant blink, or a “dissolve”.

Bug ? Feature ? Limit ? Can I make it happen in the first place ?

Thanks for any answers

— Versions —

LibreOffice
Version: 4.4.5.2
Build ID: a22f674fd25a3b6f45bdebf25400ed2adff0ff99
Locale: en_US

Adobe Reader XI
Version 11.0.12