Q: Photos.app Albums not showing/syncing to iMovie

I'm trying to import specific videos from an album in Photos on my iMac to iMovie for a new project. However, under the Libraries column in iMovie, when I choose the Photos Library, not all my albums are showing/syncing. The preset smart albums like Panoramas, Videos, Slo-Mo, Time-Lapse, old iPhoto events, etc. show up just fine. But the ones I created just won't sync. When I check Photos on my iPad and iPhone, the albums I created are there, so Photos and iCloud Photo Library are syncing just fine. It's iMovie on my iMac that isn't picking it up. I've tried quitting both Photos and iMovie, restarting my iMac, nothing.

Any suggestions on what I can do? I know I can pull the video from the videos smart album, but that album has over 800 videos. I'd rather use the albums I organized then having to sift through 800+ videos to get the project done.

I'm running 10.10.5.

Thanks in advance for your help.