Not a bug. It's working correctly.
Team 1 starts with a full clock (I think it's 8 minutes but could be off). You reach the bridge with 1:30 left. When team 2 starts they should of started with only 6:30 on the clock so all they have to do is get as far before the clock ends. Now it's completely possible that there is a bug and team 2 is not getting a shortened clock. I haven't PvP'd since 1.4 so bugs are possible but since the last PvP changes months ago it always has been as long as team 2 go to the same point before their clock ran out, they won.
You could be on to something with this one. If the 2nd team didn't get the shortened clock, and it started at 8 min, the game would end with them loosing at 1:29 left. So even though it could look like they had 1:29 left to get further, they really lost.
It looks like we're all going to have to track the clock a little more for the foreseeable future to see if this is a bug.