[Twin][1.1.27] Converting to a scenario from save sometimes throws an error (Simulation + Scenario::loadingUpdatingFlag)

[oof2win2]

I was working on my mod. When converting a scenario to a save, I get an error thrown. I did this multiple times and this was the only time it threw, so I believe this is not from my Lua stuff (it's also a C++ error). The mod has an only requirement of Factorissimo2, but I was using jarg's debug utilities too.
I don't know how exactly this happened, as when I re-launched and tried to create the scenario again, it completed the task completely fine.

[Twinsen]

It's because of a rare race condition related to main menu background simulations.

I couldn't reproduce it but it's likely fixed in Version: 1.1.28.
Thanks for the report.