This crash does not occur on iPhone devices. Tested on an iPhone X device.
When switching environment capture to manual for iPad, the crash did not occur.
1. Have an ipad.
2. Grab AREnvProbe from Sandbox -> AR
3. Package with default settings for iOS. (AR_session config should have Environment Capture Probe Type set to -> Automatic)
4. Install and launch app on an iPad pro.
App crashes after starting an AR session
Able to run on all devices with automatic capture
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-86540 in the post.