Lookup Filtering Prevents Auto Fill (v2019)

PHPMaker 2019.0.10
Adding any type of lookup table filtering to a table field, will prevent the auto fill process on that same field.

EXAMPLE:
I have a main table: ‘registrations’
There is a select field in ‘registrations’ table called ‘partID’ which stores the primary key value of a participant from the ‘participants’ table.
(the ‘participants’ table stores firstname, lastname, address, etc. of past participants)
I have a lookup table ‘countries’ - and in this table I have a filtering field named ‘countrycode’ - which is a perfect ISO 3166 Alpha-2 country code of that country.
Next I have another lookup table called ‘stateprovince’ - which also has a field named ‘countrycode’. The ‘countrycode’ of every single state / province is accurately filled with the appropriate associated countrycode.
When a ‘country’ is selected in the ‘registrations’ table, it is the ‘countrycode’ value from that table that gets stored.
When a ‘stateprovince’ select field is clicked in the ‘registrations’ table, the options are filtered by the ‘countrycode’ of the country selected above. This works great.

The problem is, if the ‘partID’ select field is used to select a past participant, the auto fill is supposed to populate the ‘address’ ‘country’ and ‘stateprovice’ fields from that participants record in the ‘participants’ table. All fields get correctly filled except ‘stateprovice’ due to its filter. If I remove the filter, it will get auto filled correctly. Re-applying the filter prevents the auto fill on that field again. I’ve tried using the ‘parent field’ filtering strategy, as well as the ‘filter’ client setting itself. They all have the same outcome.

Can anyone advise how to utilize both a select field filter AND an auto fill on that same field?

Thank you,