Here's another one: Danny Briere's left-circle shot just before the final buzzer sounded bounced off the crossbar.
"Just the way things are going these days around here," said Briere, who returned to the lineup after missing 10 games with a concussion.
The Flyers have lost four straight for the second time this season, but it's the first time they have done it in regulation.
During their current skid, they have a total of three goals in the four games.
"We didn't do enough in the offensive zone to deserve to win," Briere said.
Sabres backup goalie Jhonas Enroth, making just his sixth start of the year, made 29 saves and notched his third career shutout in 50 games.
Mason played brilliantly for the listless Flyers, but he surrendered the bizarre goal that enabled Buffalo to end a two-game losing streak.
"The boards were lively and it's almost like a set play for them, I guess," Mason said. "It's just a real frustrating way to lose the game. We were right there and guys were pressuring them when we had the empty net" at the end.
The 6-foot-4 Mason made his second start since being acquired by the Flyers from Columbus, and both have been impressive. In three games with the Flyers, Mason has a 1.74 goals-against average and .934 save percentage.
"There's still a learning curve, obviously, and there's things I still want to improve upon," Mason said. "But the start so far, with the exception of not getting the wins, I've been comfortable with. I'm really enjoying it here."
The Flyers are not sure if they are going to buy out Ilya Bryzgalov's contract after the season, or have him and Mason battle for the No. 1 job next year
Mason didn't have an abundance of work Saturday, but he was severely tested in the second period. He responded with a trio of terrific saves, including a post-to-post move to rob Drew Stafford in front. He denied Cody Hodgson from point-blank range midway through the second, and used his glove to stop Thomas Vanek's ticketed right-circle blast with 7:40 remaining in the period.
Contact Sam Carchidi at firstname.lastname@example.org. Follow on Twitter @BroadStBull.