DS4's architecture was designed to squeeze as much context as possible into available VRAM, to save on GPUs and serve as many users as possible. As a result, DS4 often loses track of the original prompt (or what it did five minutes ago), because during token generation it doesn't see the context in full; it sees an overcompressed version that loses a lot of detail. Other models use lossy compression too, but from what I know, DS4 compresses everything more aggressively.

And DS4.1 now seems to compress things even more aggressively than DS4 (4x)