They just screwed up. They installed the device a day late and outside of DC.
From the last footnote in Alito's opinion, In this case, the agents obtained a warrant, but they did not comply with two of the warrant’s restrictions: They did not install the GPS device within the 10-day period required by the terms of the warrant and by Fed. Rule Crim. Proc. 41(e)(2)(B)(i), and they did not install the GPS device within the District of Columbia...
From the last footnote in Alito's opinion, In this case, the agents obtained a warrant, but they did not comply with two of the warrant’s restrictions: They did not install the GPS device within the 10-day period required by the terms of the warrant and by Fed. Rule Crim. Proc. 41(e)(2)(B)(i), and they did not install the GPS device within the District of Columbia...