It is a coincidence that this happens merely 11 days after puzzle #66 was won (see https://news.ycombinator.com/item?id=41547395) since the expected time to solve this puzzle is a few months with a few hundred GPUs.
With puzzle #67 the public key in the transaction becomes known to all when the solver attempts to withdraw the funds, so some people rushed to compute (in 2^33.5) the private key and manage to find it in seconds/minutes.