Looks like a few months ago the meta-box plugin started forcing the field's taxonomy parameter to an array but the admin columns plugin expects it to be a single string value. This is causing the column to never be filterable.
See this commit https://github.com/wpmetabox/meta-box/commit/b894acc58d587a8274c7b970e4951cb77d16b19e
Thanks for the awesome plugins!
