Hey there @booey811 
I really wish I could confirm otherwise here, but at the time, this is the expected behavior indeed. It is not possible at the time to use the items_by_column_values query for columns that support multiple values, which also includes columns like People, Dropdown, Tags and others. Here’s a community thread where this was referenced earlier as well:
Items_by_column_values for columns with multiple values
I hope this helps 
-Alex