Yeah, just dropping it is what you're *supposed* to do. I'll take a look, thanks for the report!
For added clarity: it DID work the first time, the first time I found a scroll and used it, it teleported me back to lvl 2 where the moonstone starts. But after picking up and dropping the moonstone elsewhere, and then using a scroll, it just says something to the effect of "the spell has no effect".