🚀 go-pugleaf

I'd have to see the file to know for sure what happened, but I suspect a Frame object ID numbering conflict of some kind. 

In FrameMaker, cross-references (which are quite a different thing from hypertext links) specify jumps to cross-reference markers, which are objects with unique ID numbers. When you convert to PDF, such links become jumps to named destinations, where the destination name includes the Frame ID of the source cross-reference marker. 

When you cut and paste markers to a different document, they get new IDs. Somehow, Frame normally sorts it out, but I can see where it might fail if the new document already had a marker with the same number as the one you were pasting, or you pasted it twice, or who knows. Anyway, you might end up with duplicate named destinations, one of which could be on the same page as the link itself, so clicking jumped to that unsuspected duplicate without appearing to do anything. 

If you have or know anyone with the full version of Acrobat, it is possible to figure out what happened by examining the link and table of named destinations. I don't have Acrobat 5, but would be willing to look into your Acrobat 4 file if you want to send it to me (click on my name above for contact info). 

Essentially, though, I suspect it was a fluke. I do this sort of thing all the time and have never had this problem with either Acrobat 3 or 4.