Mounting a Pak file in 4.15 breaks the file system

Here’s my answerhub conversation with myself: https://answers.unrealengine.com/questions/595130/level-streaming-failing-on-415-mac-ios-only.html

The skinny is - calling OnMountPak or FPakPlatformFile::Mount prevents further loading from Content (such as level streaming).

It only fails on Mac and iOS packaged (MAC PIE works fine).

It continues to work on PC, PIE and packaged…

Given I’m targeting an imminent release on iOS this hoses me completely. I may need to work out how to return to 4.14.