Just one week after receiving the approvals necessary to move forward, D.C.'s $720M McMillan development has been appealed for a second time.

Friends of McMillan, the same group that appealed the project the first time, filed an appeal with the D.C. Court of Appeals Wednesday that could potentially delay the long-stalled project for several more months.

The appeal, first reported by the Washington Business Journal, was launched against the Mayor's Agent for Historic Preservation. The Mayor's Agent last week gave McMillan the second approval it needed to move forward, after it received a unanimous Zoning Commission vote in September. The Zoning Commission has yet to file its written order, which would begin the window when the opponents could appeal that approval.

In its approval order, the Mayor's Agent said any further delay of the project would be an "exercise in obstruction," adding that the opponents have not suggested any plausible alternative plans.

The development would be built on the 25-acre McMillan Sand Filtration Site at the intersection of North Capitol Street and Michigan Avenue NW. D.C.'s Deputy Mayor for Planning and Economic Development is partnering with Jair Lynch, Trammell Crow and EYA on the project. It would bring 655 housing units, 1M SF of healthcare space, 125K SF of retail anchored by a Harris Teeter, a 17K SF community center and an 8-acre park to the abandoned site.

The project was first approved in 2015. The development team held a groundbreaking ceremony on Dec. 8, 2016, only to have the D.C. Court of Appeals vacate its approvals the following day. The move, along with the court's blocking of Brookland's 901 Monroe project, set off an unprecedented wave of appeals that has delayed over a dozen projects and thousand of housing units across D.C.

Trammell Crow Principal Adam Weers said he is not surprised to see the appeal and is confident the court will rule in the development team’s favor this time around. He cited the court’s dismissal of an appeal over Ditto Residential’s Union Market-area project as a sign the judges are starting to view these cases differently.

“I feel like you can see a shift in the Court of Appeals’ actions on a lot of these other cases,” Weers said. “The court is starting to recognize this relatively small group of people that has their hand in different things is utilizing the court in a way it’s not comfortable with.”

UPDATE, APRIL 12, 4:30 P.M. ET: This story has been updated to include comments from Trammell Crow Principal Adam Weers.