Harley opened the scoring 4:51 into the first period to put the Stars up 1-0, taking a drop pass from Joe Pavelski and shooting past Markstrom’s blocker.
"Everyone loves scoring goals," Harley said. "I'd trade it for a win, though."
Tanev tied it 1-1 at 8:02 after his centering pass from the right side deflected off Dallas defenseman Ryan Suter's skate and between Wedgewood's legs.
Hanifin put the Flames up 2-1 when he batted a loose puck in the crease over the goal line at 15:30.
Marchment tied it 2-2 at 19:00 when he shot past the blocker of Markstrom after Miro Heiskanen's point shot hit Tyler Seguin and dropped to Marchment in the slot.
Marchment scored again on a penalty shot 1:49 into the third when he beat Markstrom glove side to give Dallas a 3-2 lead. Marchment received the penalty shot after he was hooked by Tanev on a breakaway.
The Stars have failed to hold a third-period lead in four of their past seven games.
"A lead with whatever, under five (minutes) to go when they scored that other one, it feels like a little bit of one that slipped away again," Wedgewood said. "It's unfortunate, but maybe if you look at the statistics of what they were doing to us, maybe it was a point earned. But obviously, in our locker room, having a lead with five minutes left to play, that's a point lost."
NOTES: The Flames had an NHL-leading seven comeback wins in November. ...Calgary outshot Dallas 11-1 in the second period and 26-6 after the first. ... Tanev had four shot blocks to reach 1,501 in his NHL career. ... Pavelski had an assist to extend his point streak to eight games (five goals, four assists). ... Earlier Thursday, the Flames traded defenseman Nikita Zadorov to the Vancouver Canucks for a third-round pick in the 2026 NHL Draft and a fifth-round selection in the 2024 NHL Draft that Vancouver initially acquired from the Chicago Blackhawks.