After following the instructions of CA APM Implementation Guide to define an asset extended field shared with CMDB, the date fields are not displayed as a date field.
On top of the steps described in the Implementation Guide you will need to run SQL queries for each date field you add.
NOTE: before going ahead with any SQL update you should make sure a full valid backup of the MDB is available.
The below queries should be executed against the MDB, changing 'field_name' and 'attribute_name' accordingly to match the CA CMDB fields you are configuring in APM.
UPDATE arg_field_def SET data_type=99 WHERE table_name = 'usp_owned_resource' AND field_name='nr_exp_dt'
UPDATE al_form_attribute_def SET control_type_id=10 WHERE class_name='usp_owned_resource' AND attribute_name='nr_exp_dt'
After that execute IISRESET on the APM Application and Web Servers.