Whats with anti air being able to lockon below 30m now?

As the title is stated, Since the release of the Iwo Jima update I've consistently been locked on/shot at with AA weapons well below 30m sometimes as low as 5m to the ground while still having people continue to maintain lock & fire.  During these times I'm not soflam'd/designated or rao hacked either.  Whenever I try to do it myself I cannot reproduce this as the person(engineer) using the fxm or in a wildcat using missiles. Is this a new bug or a new hack? Because its consistently happening everytime I'm in a air vehicle,  specifically helicopters where I can easily maintain below radar but am still being locked on. I've never experienced this issue prior to the Iwo Jima update.