I'm not sure if it is a bug, and if it is, it is a very minor one, but...
The Auction timer is supposed to run until auction end time, and be updated to allow full three minutes before auction ends from any bid made during the "three minutes warning" (being at the last minutes of the auction).
I think that there is a (very) minor bug that reset it when the time is at the three minutes period prior of that "three minutes warning" time.
Meaning, an aucition ends at 00:30:00, and being bidded at 00:26:00 will cause an additional three minutes to be added. By that the new time for ending an auction will be at 00:33:000, and a total of 7 minutes to the aution end time.
Am I right?