Hey Nelson,
Great question. I think I'd call this a bug, but one that was done on purpose...
Obviously the point to Client Map filters is that they limit what you see in the View according to whatever rules you set - i.e. it only shows submissions with data that maps to specific values in the account of the user who happens to be viewing the data.
But creating a brand new submission will by default create an *empty* record - and that DOESN'T map to the user, so the submission won't show up in the View. So after creating it you get booted out back to the list view right away & nothing seems to get added.
To get around it, generally you'd just remove the option to add submissions in that View (Forms -> Edit View -> General tab -> "Can add Submissions"). That's by far the simplest workaround. But you could also probably hack around it by using the Submission Pre-parser module to pre-fill the form field you have the Client Map filter set up with, the moment a new submission is added from within the Form Tools UI: and fill it with whatever value is appropriate from the user's own user account. That would ensure that the moment it gets added, that field contains the right value to allow it to appear in the View.
I'd need to experiment to get it going, but in theory that would work.
But... to return to the main point: I'd say it was a bug.

Definitely a UX bug in the very least. Perhaps by entering a Client Map filter it should warn you that the "Add Submission" feature won't work - or even aggressively auto-disable the option altogether (?). Something to keep in mind for future versions of the script, thanks!
Ben