Hey Paul (and anyone else experiencing this),
They were finally able to reproduce it, using the video I sent in. It took two rounds, since they had a pretty old version of OpenOffice installed. Their advice was to tell my users to use FireFox, and to remind them to use the Paste from Word button. Of course, I can't tell over a million active users what browser to use; I've gotten blasted before for recommending one browser over another...
Anyway, the plot thickens! Microsoft Word does the same thing when pasting from Chrome, in IE, on the PC! They wanted another video, to prove it.
So I gave them one better -- a plain old HTML document from TextEdit (Mac's version of Notepad), pasted into the editor while in HTML mode, showing spaces where they should be. On postback? Bam, spaces gone.
Now, since I did up a video and all, and since it's very possible I won't hear from them for another 4 days (that happened last weekend), I uploaded the video to YouTube
to share with you guys here.