Thank you for that Nox,
I’ve placed a feature request in, although I don’t believe this is something that we would be able to catch without adding invasive checks that would inhibit performance. I’ll leave that up to the developers however. You can find the feature request and track it here: UE-40811.
As for why the issue doesn’t happen until the project is reopened; This is due to the crash coming from the engine trying to load all references when loading an asset for the first time. Since, when you are setting up this reproduction, all of these blueprints are already loaded, it doesn’t have to load anything else. As soon as you ask it to load one when opening the project up again however, it tries to find all of the references and goes in a circle until it eventually times out.
Also, the reason you got that message “You do not have any debugging symbols required to display the callstack for this crash.” is because you don’t have the Editor Symbols for Debugging enabled in your installation. That can be found in the Epic Games Launcher’s Library tab by clicking the arrow beside launch on the individual installation and selecting “Options”. It’s quite sizable but it will let you see your own callstacks. Either way, (for future knowledge) if you submit the crash and provide us with either the MachineId or EpicAccountId, we can look it up internally.
Have a nice day!