Renamer not finding meta data so is failing

I have my first simple flow; i am transcoding varying .mkv files to HEVC format. At the end, I want to rename the files to {title} ({year}).{ext} format ... but no matter what file is transcoded (and that works beautifully), i end up with a file named '.mkv'; basically a fully functional video file with no title. The logs say that no meta data is found for Renamer to work with. I have the 'Renamer' tile at the end of my workflow, after the 'Move File' step in the workflow (which also works fine). The relevant portion of the log is:

https://preview.redd.it/kywmqrzfcvte1.png?width=2494&format=png&auto=webp&s=7472d98d37402db85768061ab9d7164c33384871

Thanks for any help! I really am loving the app!