A very visible example of why some delivery dates matter more than others within a larger project program, however I suspect they approached this as a handover

A very visible example of why some delivery dates matter more than others within a larger project program, however I suspect they approached this as a handover milestone as in there was little to no scope for the JPL teams to participate in and respond to testing with code changes. If any contractors were involved I hope there are no delay penalty clauses because waiting for the next launch window is a lot of idle time to be on the hook for!