Offers are not made public in the highly confidential negotiations.
A fuzzy report of an offer might be leaked out by an underling who risks losing his or her job with the team or with the sports agency.
I suspect J.D. Martinez has several offers and any Red Sox offer, pending or expired, is/was not the best offer. Martinez, thinking that the Red Sox are under the most pressure to sign the top free agent hitter, may be waiting for the Sox to top the current best offer.
Or not.