This filter is not able to handle all records with non-integer entries in the Date of First Publication field at the Title Level. This field is actually a Display field.
On the old site, there should be a data table with only integers that handles the filtering -- this removes brackets, etc., from the Date of Publication field. I think the same thing happened here as with Date of First Performance (Annals), which is that on the old site this table was a date RANGE, with anything in that range being hit by a search that encompasses it. Somehow this table was not imported.
This filter is not able to handle all records with non-integer entries in the Date of First Publication field at the Title Level. This field is actually a Display field.
On the old site, there should be a data table with only integers that handles the filtering -- this removes brackets, etc., from the Date of Publication field. I think the same thing happened here as with Date of First Performance (Annals), which is that on the old site this table was a date RANGE, with anything in that range being hit by a search that encompasses it. Somehow this table was not imported.