Identical feature on two devices but different behaviors/scenarios for BDD testing

We have two versions of an app : Desktop / Mobile

On desktop we have to go to the detail page of a panda -> we click to the change anniversary date button -> pop up where we can enter the new date, we validate and it's done.

On mobile we have to select the menu change anniversary date -> new page where we enter a panda name -> we are send to a new page where we enter the new anniversary date. We validate and it's done.

If I found easy to write scenarios for the desktop, for the mobile I'm blocked on the possible scenario to select a non existing panda. This behavior can't exist on the desktop since we have a list of panda and we have to click on one to go to the detail page. Instead of that, on mobile we have to enter the name of a panda so it's possible we enter a non existent name.

And I'm blocked because the new feature offered is identical on both device. Do I need to make my behaviors/scenarios match between Desktop and Mobile or is it okay that my behaviors/scenarios are a different based on the platform ?

Thank you for your help !