I'm not sure it's be reasonable to leave an actively exploited critical bug until August. Nor would I be too interested in playing middle man or paying for support from curl to get it out.
The responsible thing would have been to simply wait another month, considering you've been warned about the delay.
Naturally some people find that this offensive since this puts a price to that “bliss”.
And if you find something halfway through the month then oh no two weeks to reply, that's basically a standard business interaction at that point.
There's no such thing as "responsible disclosure on a technicality". Don't be a dick, and work in good faith to keep users safe.