Have PostProcessing AO with transparent material on iOS

Hello,
I'm trying to have Post-process Ambient Occlusion on iOS but when AO enable, all the mesh with transparent standard shader are not visible on iOS but works as expected on Android.
Did I miss something required ? I found this issue that seam corresponding : https://issuetracker.unity3d.com/issues/ios-post-processing-ambient-occlusion-does-not-work but in fixed state...
I'm using Unity 2019.3.0b3 and Post Processing 2.1.7