Custom type doesn't allow checkbox (dynamic UI)

Hi, I have a custom type with 3 fields: name (string), qty(string), isReady(boolean). On a custom action, I'm adding those values in a list created in an FFAppState variable.

When I try to retrieve, the values into a dynamic generated list, ]I have a problem, as I get:

My settings for the checkbox are:


Without the checkbox widget rows are shown correctly, how can I fix?