Noticed different behavior in a couple of text fields with number formatters. On one I could type an aperture (e.g. 5.6) and it only finalizes the formatting on submit. The other is greedy and tries to format as you type, so that 5.6 ends up as f/56.
I tracked it down to different flows for handling selection. The misbehaving one has a direct database query in the view, so I think when the model changes the view invalidates, and the text field formats



