Songs stuck in "waiting" mode on iCloud library

Some of the albums that I buy and import into the Mac Music library only partially upload to the iCloud library. As a result, many of the songs aren't available on my other devices, like my iPhone. They show as "waiting" in the iCloud status field. In some cases I can delete them from the library, re-import them and they work fine, but this only works some of the time. It's really annoying, as sometimes only half the album syncs and the rest doesn't. Is there a secret to forcing the songs to sync?