Hang during play "gpuEvent - firmware detected lockup"

Hey, so I’m testing my game on my iPhone 5s (iOS 10.3.3). During play the game will randomly pause from anywhere between 1-3 seconds. I can’t find out where this slow down is occuring. I started looking at the analytics logs on my device and noticed hundreds of “gpuEvent” logs. Opened them up and saw this

gpuEvent-myProject
bug_type: 284
restart_reason_desc: “firmware-detected-lockup”.

I haven’t been able to reproduce the slow down on an iPhone 6 - 7. Seems to jut be a 5-5s thing.

Any ideas what this could be? Or how I may diagnose this problem? The profiler is little help. Just get big spikes in “WaitForPresent”. I don’t have access to a Mac, but maybe I’ll have to go buy one and test in xCode. Sigh. Also, sometimes I can play the game for 15 minutes without a hickup.

Impossible to find any information on “bug_type 284” or “firmware-detected-lockup”.

Anyone? Unity? I really need some help here, I’m not even sure how to diagnose this?

How can I track down the culprit for a “firmware-detected-lockup” error?