I've stumbled upon that too! Funnily I see it having two forms:

1. Some bad idea gets embedded into the context that you just can't argue away

2. Some important idea gets lost in compression and the ai wheres off into funland without recourse.

In both cases if is often better to start over or just do it yourself. I sometimes find myself asking for a summary, editing it and then using the edited one to seed a new session.

Edit: s/Finland/funland/