ThingTheWiz: How could I have missed it?
Because it violates any usage experience and usability insights by not being where you expect it to be from past experience, nor behaving the same way you can reasonably expect. That big button must be a convenience addition to the usual clicking on the "paused" icon of your download (which must work as a toggle) or the additional "resume" button next to it, not a replacement. The way it is is just bad design.
Edit: oh, I noticed the post I responded to is a tad stale. :\
Things have changed to the extent that you can't even selectively pause a download anymore.
@ksb5: I did some tests but could not provoke such a situation. Has there been an update to the paused game meanwhile maybe, or insufficient drive space? I'd expect that refunding a game while it's download is paused might yield interesting results. Maybe just close and reopen the client, it is buggy in other respects so why not in this one as well...