Air carrier First Officer reported receiving an apparently erroneous momentary GPWS terrain warning on approach to ROA.

Narrative

Had a flight today to ROA. As setting up to descend into ROA we got the weather and notams. Winds were favoring Runway 24 so we started to set up for the RNAV Y 24 approach. We briefed all the terrain; and reviewed the company pages again since this is an airport known for unstable approaches. Approach Control vectored us onto the final approach course and told us to maintain '4000' I believe until established on the approach course. The FAF altitude was 3700. The Captain was flying this leg; and disconnected the autopilot and was hand flying during the intercept. We maintained 4000 ft. until we were fully established and almost right on the snowflake. We started a gradual descent (roughly 500-800 fpm) to get to 3700. After the final approach fix we were doing a normal RNAV (CAMPA) approach. We were on the snowflake if not the slightest bit high; as we were visual and didn't want any aggressive descent rates due to the terrain. We were visual the entire approach. I can't remember exactly how far past the FAF we were but we got for a brief second the 'terrain' the light barely even flashed on the 'GPWS' button. When we looked down we weren't more than 1000 fpm if anything more of 600 slightly above the snowflake and we'll clear of all terrain. So we continued the approach as we were stabilized. After the brief aural 'terrain' and light flash we didn't get anything else; nor nothing from ATC. Don't know if it was a malfunction of the terrain detection system; but wanted to write this brief summary.