I've had challenges filling out forms on Safari for quite some time and haven't seen it improve with iOS updates. Specifically, sometimes I'll double tap a text field but it won't go into text entry mode. Sometimes I'll choose an option from a dropdown box using the picker control that appears but will find that my selection wasn't retained once I navigate away from that control. I also have experienced checkboxes that won't check, no matter how I try. In some cases, I believe what happens is the VoiceOver cursor gets out of sync with what's actually visible on the screen, as if perhaps the system focus isn't following the VO cursor as I flick my way through a webpage. I find that if I manually scroll the page using the 3-finger swipe and then drag my finger around until I find the desired control, it often behaves normally, but on some pages it's near impossible to manually find a control and flicking through the form controls is much easier. Anyone else have this issue?
For an example, try filling out the advanced search form at www.flexjobs.com. Also, same for the job search page of Apple.com too