In SharePoint there is a limit on number of lookup columns that can be used in a single view. This means that MetaShare workspaces cannot have more than 12 lookup columns (managed metadata and person or groups columns) selected as view fields. Additionally, the sum of lookup columns used as view fields and selected as filters must also not exceed 12.
Once exceeded, so when a 13th lookup column filter is applied, there will be a warning shown and MetaShare will display search based results instead of query based results.