I have forms that work perfectly on the desktop. When I open them on a 2018 iPad with the latest updates to iOS and Acrobat, they work almost perfectly.
On the iPad, when I select the field that has been formatted as a date (I used Acrobat Pro DC with latest update), the calendar dial opens. I can select the date without issue. However, if I hit the "Next" button to tab through the form, the calendar dial doesn't go away from the screen (I have to tap the screen multiple times for it to disappear even though the date is already filled). I can type into text fields without issue, but when I reach the first dropdown, it won't open the list. The dropdown field is highlighted in blue so I know it's selected. The only solution I have found is to close Acrobat Reader and reopen it, then I can continue filling the form.
Something with using the "Next" or "Previous" buttons and the Date field is causing the issue. I don't know if this would help, but the date field is formatted as mm/dd/yyyy.