It appears all your Masked Entry controls share the issue, apparently because they employ keyboards that use a "Next" key rather than "Done". Unfortunately "Next" automatically tries to start an entry in the next entry control it can find (even if on another tab within a Tabview), whether I wish it to or not. I am beginning to suspect this is a generic issue in Maui, as opening a page that contains an entry control within a stack also automatically opens it for entry, sometimes a convenience but more often a pain point that will be hard to explain to the user.

What I want to do with "Unfocused" (or any similar event that only happens when the user is no longer entering data within the control) is to send the data to the Page (or View) Model for processing, just as I can do with controls that use a "Done" key. For now I will probably avoid all your Masked Entry controls until they have such an event. The best fix would be to replace their keyboards with ones that do.