My workflow is the following.
I download all images from the card to a folder on my MacBook Pro. Sometimes I leave the originals on the card for a few days but typically I clear it off pretty quickly. The way I do this is I select the images (from the mounted card) in PhotoMechanic and delete them. Then, with the card still mounted, I empty the trash and then eject the card. Then I reformat the card the next time I put it in the camera. Been doing this for years.
The issue is that there appears to be no files to be deleted in the trash, now, after deleting them in Photo Mechanic. This happened after I updated to macOS Sierra.
I am just wondering, since I have selected the option to "Move files to the trash after deleting" in Preferences, if this may be a bug of some sort. I can get around it by just reformatting the card, like usual, but it's different than before and seems to be something that isn't working correctly.