Alternately, it's possible that it can't be replicated. Just as Timo
points out above, many food-stuffs are difficult to replicate properly, so it's not at all a stretch to assume that certain other materials are difficult to generate this way also.
We've seen pure latinum in "Who Mourns For Morn" and it looked like silver paint fresh from the jar. Assuming it's a metal, then the fact that it's a liquid would suggest it's some sort of mercury amalgam, possibly with a noble metal like platinum. I don't know how well those two could combine, but evidently the Ferengi (or somebody) developed the right secret sauce to make it work. From the same episode, we see that the "gold pressed" nature of gold-pressed latinum is that the silvery liquid is somehow suspended inside the gold bricks. Quark is able to fairly easily break one of these bricks in half with his hands which suggests that either he is waaaay stronger than he looks (doubtful given the number of scraps we see him in where he doesn't get the upper hand) or that the gold is manufactured in such a way that the structure is a much more porous volume which is later infused with the liquid latinum. When Morn regurgitates a little spitful of the stuff for Quark, the amount is valued at an astonishingly high figure (like 100 bricks IIRC) which suggests that a little goes a long way and that the gold vessels are mainly there to provide a convenient and attractive means of handling the latinum.
I posit that the process for creating latinum itself is tricky and the resultant material is not entirely stable. As a result, maybe it can't be re-materialized in it's alloyed form. Do we ever see gold-pressed latinum transported? (We very well might have... just I can't think of a time doesn't mean it didn't happen.) If not then perhaps it's just a matter of that. If you can't rematerialize it, then you can't replicate it. If, OTOH, it transports fine, then my idea is out of the water.
In any case, all we can do is speculate, since it was never said on screen one way or the other.