Insurance tech Corgi on Thursday announced a $106 million Series B1 raise, valuing the company at $2.6 billion, just three weeks after announcing a $160 million Series B at a $1.3 billion valuation and four months after its $108 million Series A. The company offers insurance, working specifically with startups in areas like tech, cyber, and general liability; it counts Deel and Artisan among its customers.  Even in the current go-go dealmaking environment, that sequencing is remarkable. While startups raising back-to-back rounds at steep step-ups have become almost routine, a company whose valuation doubles in three weeks is unusual enough to raise questions, particularly given the investor set in both rounds is the same. Asked what material event justified that kind of jump in such a short window, investor Kanyi Maqubela of Kindred Ventures cited the company’s momentum. It’s an explanation may satisfy some, but the practice more generally is starting to attract scrutiny in LP circles.…