Horn continues to go off after horn fuse pulled in Kia Sportage 2017

I woke up to my Kia Sportage 2017 horn blaring. Hitting unlock on the keyfob would stop the horn for ~0.5 seconds with each press. I located the fuse compartments but was unable to pull the fuse without tools. I tried starting the car, and within 30 seconds the horn stopped. I then removed the 15A horn fuse in the engine compartment - it was not blown.

About 20 minutes later, the horn started blaring again. I started the car again and within a minute the horn stopped blaring. I have since removed the B/Alarm relay and the batter from the keyfob. The horn has not blared again, although it has only been 15 minutes since. Is this a relay failure mode? How would the horn keep blaring after the horn fuse was pulled?