Tool keeps saying "For the date you selected, we were unable to find any availability, please select an alternate day."
But EF shows plenty of availability

Thoughts?

I'm trying to book my next DONE4, but I keep getting this error message
As a specific example, I'm getting the message when trying to select JFK-HKG for October 1st
EF shows that Cathay Pacific has four flights that day, three of them showing D9 availability (and the fourth shows D0)
I've also tried the day before and the day after, with the same result (there's also decent availability those days according to EF)