I spent some time testing what I had to consistently recreate the issue. Yes this is a project I converted from 4.16. First of all it’s only happened in builds that I have uploaded to steam. I have tried running the build directly and it doesn’t crash. The crash happens when I try to load in a streamed level. 3/5 of the levels always load with no problem, sometimes the remaining 2 will load ok, but one of them always crashes it. It is usually the message I posted above but I have seen this one as well.
https://puu.sh/xcxIQ/81a95dff83.png
The real kicker is why it consistently works with most of the levels. And how it’s only broken through steam.