When an save is loaded going into a Fall season, it creates a new intelligence briefing as it normally would. However, in the case of an autosave, the game does not distinguish between a game heading into a Fall season and one saved at the end of the Fall season that resumes that season. Basically, it's issue #204, but for Intel briefings.

This wouldn't seem too bad, but the game records a history of all the Intel briefings, so if this problem occurs often enough in a single play-through there will be an array overflow and other variables will start getting rewritten.