They appear to have quit using virtual line for Hagrids - it wasn’t used at all from what I could tell over the holiday.
Now that it’s pretty much gone… the trick to getting a spot was to go to the website at 8:50ish for the initial drop on a normal web browser from wherever, grab a reservation, and then don’t go back to the website until you’re in the park and ready to ride. If you didn’t go back to the website, your return time could have “passed” but it wouldn’t know and wouldn’t start the 30 minute clock on your QR code until you visited the website again.