Under the current scenario, any solution that uses a Pen Input will always show a Medium severity warning in the solution checker.
The rule name triggering this is "app-include-alternative-input".
It recommends that a TextBox be included as an alternative input method for accessibility purposes. However, there is no way way for the checker to know whether a TextBox has been included on the screen for this purpose.
There is a problem with the expected behaviour as a developer should be able to use a Pen Input control without always then having a Medium severity warning raised in the solution.
Proposal: Add an extra property to the Pen Input control that allows a user to reference which TextBox (if any) has been made available for alternative input. Then, update the logic of the "app-include-alternative-input" rule to only display a warning if this property is empty.