I'm having an issue where I have a normal html form in a scrollable panel item (not a FormPanel, just form html), as I tab through the form fields, when I get past the last visible input field, the panel gets adjusted to bring the next field into view. This seems to conflict with the panel scroller, because after this happens, I can't scroll up anymore. Scrolling doesn't break if I tap each field and work my way down, but it I tab through the fields it breaks the scroller. The top half of the view is permanently un-reachable via the scroller.
Why aren't you using a ST2 form panel? It sounds like when you are tabbing through the items the iOS scroller is working but when you scroll with your finger (or mouse) you are using the ST2 scroller so you have two different scrollers working and conflicting.