I’m not sure I understand the question. Are you asking “How did my road get to having this odd looking shape?” or are you asking “Given my road, why didn’t I get more warning about my eep day?”
My answer to the former is “I have no idea / did you do this on purpose?”
My answer to the latter is: Non monotonic roads reveal some of the oddities of Beeminder’s “lane” concept. There’s a lot of talk about “lanes” and “if you’re in the right lane today you can’t derail tomorrow” but strictly speaking it’s all lies, hinging on a monotonicity assumption. The truth is that your “lane” is determined solely by your position relative to today’s road’s critical edge. So you will always go from green straight to red in a situation like this.
Apologies if you were interested in the former question and I’ve been no help whatsoever.