This is a dirty fix to force Unity Garbage collection before loading a mission, because it seems that if it triggers during loading, the loading breaks.
It is very much a shot in the dark, before doing actual debugging and finding what is causing the memory to be filled.
Also I get a stream of NullReferenceExceptions from PostProcessingBehaviour when I have no advanced video options enabled. As these were clogging the output_log, I've rerouted them to the mod's Log.
As said, all very dirty and might do more harm than good!