To be clear, there are no rumors that say the Miami Dolphins could will, or maybe scheduled to play twice in London as part of the leagues International Series. The Dolphins will play one game, a home game yet to be determined.
The Dolphins opted to give up a home game in 2020 with the hopes of landing another Super Bowl in the future. The NFL requires a team wanting to host the Super Bowl to play a home game in one of the International series games.
Last month a rumor was being circulated by FOX Mexico that Miami would be heading to Mexico City in 2020 but the NFL said that was an erroneous report (or simply “we won’t confirm that because they stole our thunder”).