I have frequent issues trying to enter the First Lounge at Heathrow, flying BA but with Oneworld Emerald status from Qantas. For some reason it doesn't display Emerald on my android mobile boarding pass, and more often than not they just look at my boarding card and tell me to go to the Club lounge without scanning it. If they scan it shows as Emerald. If I use an airport printed or email boarding pass Emerald is printed on it. Maybe their is a similar issue with IB boarding passes?
I have the exact same issue, I now spend the extra few minutes getting a printed boarding pass as it actually saves time trying to enter the lounge and not have to go through the 5 minute discussion/argument to convince them to scan my mobile boarding pass to reveal my status.