When a contact has multiple subtypes a contact view gives an empty result when you filter on contact subtype.
Multiple subtypes are stored in the database in a flat field separated by a space, so the views filter on subtype should explode the field on the space character and then search in these values.
Comments
Comment #2
petednz commentedI think i just ran in to this too. another way of putting it is that in D7 i would get eg
WHERE (( (civicrm_contact.contact_sub_type LIKE '%Alpha%' )
but in D9 it comes through as
WHERE ((civicrm_contact.contact_sub_type = 'Alpha')
Drupal 9 civicrm_entity 8.x-3.0