Problem with connections being made automatically (MCPE)

I’m having a problem may just be my misunderstanding how connection works, so perhaps someone can help clarify for me. This is MCPE: As normal: A student creates some tynker code, and then /connects to it from his or her MCPE (iPad). So far so good. The problem comes when they go back to work on OTHER (usually previously-created) worlds of their own, having nothing to do with Tynker. It looks like it’s trying to reconnect to the Tynker server, and gets an error (probably bcs the server isn’t there), and it clears their inventory (which gets them upset). The problem is that these are completely separate worlds – having nothing to do with Tynker, and they have never (or so they claim) connected from these worlds. Does the /connect somehow make a sticky cross-world connection that could be causing this behavior?