I am using Flow to run an API call to an external system that in turn return a record structure, One of the records fields is a datetime field type. When I try to access the record datetime field in a screen element (or any other element) I am getting  the below error
 
class java.util.GregorianCalendar cannot be cast to class moduleapi.interaction.DateTime (java.util.GregorianCalendar is in module java.base of loader 'bootstrap'; moduleapi.interaction.DateTime is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @4ee37ca3)

below is the Apex Action I use. The Action save its output into an account record variable and then after if I try to access the datetime__c field I get the class java.util.GregorianCalendar error I reported above.Why? if I use date instead of datetime it works. If I initiate the datetime__c like this it works out.acc = [select name, datetime__c from Account where id ='0014J000004uVIUQA2'];

driving me nuts.

global class datetime_issue {

@InvocableMethod(label = 'datetime_issue')
global static list<outputCls> getAccounts() {

outputCls out = new outputCls();
out.acc = new account();
out.acc.datetime__c = system.now();
out.acc.name = 'datetime issue';


return new list<outputCls>{out};
}

global class outputCls {

@InvocableVariable
public account acc;
}
}