iOS exposureChange not correct after mraid.expand()

[gregor...@celtra.com]

Hi team,
reproducible in Mobile Ads SDK (iOS) version 11.6.0 (also in earlier versions as well)

after calling mraid.expand() and ad expands,
exposureChange emits an event with the exposedPercentage value being 0.
Which is not correct, should be 100 since the ad is still in view.

Works as expected on Android.

Min example code:

<button id="btn"> Expand </button>

<div id="output"></div>

<script src='mraid.js'></script>

<script>

var btn = document.querySelector('#btn');

var output = document.querySelector('#output');

mraid.addEventListener('ready', function() {

mraid.addEventListener('exposureChange', function(exposedPercentage) {

output.innerHTML += 'ExposureChange: ' + exposedPercentage + ' ';

});

});

btn.addEventListener('click', function() {

mraid.expand();

});

document.querySelector('body').style.background = 'yellow';

</script>

Thanks,
Gregor