I'm going to wonder if that was a BB thing or a Brady thing, struggling in Miami. I mean, of course, it goes back earlier than BB, but that was back when the Dolphins were generally really good and the Patriots were generally not that good. Maybe Mac loves playing there and lights it up. Who knows.
Or just a random cluster of losses, which will happen over the course of 20+ seasons.
Looking at the losses:
2000: Pats lost to a better team (5-11 vs. 11-5 team that won AFC East and go on to AFCCG).
2001: Brady's 2nd career start while team was still searching for its identity.
2002: Lost to what was probably the better team.
2004: A true WTF loss in a game the Pats had in the bag, with Wes Welker and Sammy Morris doing the damage in the 4th quarter. One Morris tackle was done by Troy Brown.
2006: The famous 21-0 loss where nothing went right for the Pats. Then again, it was Nick Saban on the other sideline.
2009: Pats defense was showing the warning signs that this team was going nowhere.
2013: Brady drive in the 4th quarter falls short as Ryan Tannehill torches Pats D
2014: Season opens with a loss where the Pats were simply outplayed.
2015: Truly one of the worst losses of the Brady/Belichick era. BB got outcoached plain and simple.
2017: Pats defense lays an egg while Brady throws 2 picks.
2018: Miracle in Miami play
2020: Got beat by the better team
There's no real pattern there. A couple of freak losses in games that could have gone either way (2004, 2018), as well as a couple of games where the Pats simply got beat by the better team (2000, 2001, 2002, 2020), and a handful where they got outplayed despite the disparity in record. And that one loss in 2015 where Belichick truly messed up no matter what anyone says to the contrary.
Some memorable wins down there, however:
2003: Famous OT win where the Marlins infield dirt messed up the Dolphins kicker.
2005: Win in first game against Saban
2007: Absolute domination by Brady/Moss
2008: The Matt Cassel show avenging the Wildcat loss.
2010: Pats scored on a kickoff return, a short field set up by a blocked punt, a blocked FG, and a pick-6.
2011: Brady 99 yard pass to Welker seals a win
2012: Solid, unremarkable win that was the team's signature
2016: Pats destroy hapless Dolphins to cap Super Bowl regular season
2019: Brady being Brady