Scenario errors

[sidusar]

Pardon me, but is anyone else experiencing seemingly unexplainable scenario errors? I mean situations like this:

- test scenario, it all works fine
- put down a yubo
- test scenario again, scenario error
- remove the yubo
- test scenario again, still scenario error
- load a previous save file of the scenario back when it still worked
- test scenario again, still scenario error
- bang head on desk in frustration

I'm not expecting anyone to have a solution for this, but it'd be a comfort just to know I'm not the only one to whom it makes no sense