How to fix incorrect keyword number

I use a hierarchical style of managing keywords. Today I noticed I had two redundant keywords, Bird and birds. I selected all photos in the catalog, clicked the arrow next to the number by birds to select all photos containing that keyword. Next I clicked on the left side of Bird to add the Bird keyword to those images. Then I unchecked on the left next to birds. Now no images have the birds keyword. But wait. It shows a 1. I selected Metadata, Purge unused keywords, and that didn't fix it. Next I exited LR and deleted the Helper.lrdata file since I read that can fix cache issues. Opening LR Classic again (Mac version), the keyword is still there. Is there any other way to fix this?