Seems that the JL search isn't working quite right. Given the inputs HKG-BOS on 2 May 2015 on CX, I get:
Data Source Error [RD-3]:
"Unsupported Route/Invalid Cabin Class"
If I manually search via the JL website, the search works and shows no availability. The JL site requires a return date, which KVS doesn't have an obvious input for.
tl;dr: appears that KVS doesn't correctly pass data to the JL site, or can't correctly interpret the returned data