I have abstract class with generic type. it has abstract toBuilder method as suggested here: Using Lombok @SuperBuilder annotation with toBuilder on an abstract class?

here is the abstract class:

@Data
@SuperBuilder(toBuilder = true)
public abstract class TenantConfItem<T extends DeepCloneable<T>> {

    private final URN urn;

    private final Long version;

    private final T configData;

    public abstract TenantConfItemBuilder<T, ?, ?> toBuilder();

    public TenantConfItem<T> copy() {
        return this.toBuilder().build();
    }
}

the subtype:

@SuperBuilder(toBuilder = true)
@EqualsAndHashCode(callSuper = true)
public class PointsExpirationByEarnedDatePolicy extends TenantConfItem<ExpirationByEarnedDate> implements Singleton {

}

here I'm using its builder:

val policyBuilder = PointsExpirationByEarnedDatePolicy.builder()
                .version(0L)
                .configData(new ExpirationByEarnedDate(retentionDays));

but I get an error for the configData:

error: incompatible types: CAP#1 cannot be converted to ?
                .configData(new ExpirationByEarnedDate(retentionDays));
                           ^
  where CAP#1,CAP#2 are fresh type-variables:
    CAP#1 extends PointsExpirationByEarnedDatePolicyBuilder<CAP#2,CAP#1> from capture of ?
    CAP#2 extends PointsExpirationByEarnedDatePolicy from capture of ?

I guess it is because the parent builder has 3 arguments with the generic (TenantConfItemBuilder<T, ?, ?>) and the sub one has 2 (PointsExpirationByEarnedDatePolicyBuilder<?, ?>). Any idea for workaround?