useNativeKeyboard = false is not triggering validation

[DowsingUK]

Describe the bug
useNativeKeyboard = false is not triggering validation

Code

Form
(
  key: _con.formKey,
  child: Column(
    children:
    [
        Pinput(
          useNativeKeyboard: false,
          validator: (value) {
             return value == '2222' ? null : 'Pin is incorrect';
          }
        ),
        TextButton(
          onPressed: ()
          {
            _con.formKey.currentState!.validate();
            debugPrint('validate!');
          },
          child: const Text('Validate'),
        ),
    ]
  )
)

Pinput version: 3.0.1 - 4.0.0

Smartphone:
iPhone, iPad, Android