A320
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 67
Aircraft Equipment Problem Less Severe
Flight Crew Executed Go Around / Missed Approach; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Overcame Equipment Problem
Aircraft
After cleared for visual to Runway 28R at 2;500 feet; we began visual turn to final; and descended. We received a GPWS alert and although it seemed unlikely; the Captain correctly climbed per SOP. The alert stopped and we resumed the visual approach uneventfully. We reviewed the terrain after landing and saw no threats that should have set off the alert.  It is worth noting that [another] arrival behind us experienced the same alert; which we heard them report on the tower frequency.
An A320 First Officer reported an apparent anomaly in the GPWS system when they got an invalid terrain alert on visual approach to PDX.