zoobuffalo Google Play Dashboard to find the native crash reports?
It would be select the app from the main list, then Crashes & ANR, if you are having native crashes they should show up here for the device.
I haven't changed any assets
Yeah this is fishy for sure but you didn't just change AIR versions you probably changed Android build tools etc since the last time. The AIR framework is only part of the equation, there may be something else that changed on the Android side unless you know you compiled with the exact same build tools of the Android SDK.
And maybe it DOES have to do with code Harman may have changed for their native splash??? I don't know, seems like that is the next logical leap.