I have a 2017 XC90 and until this past weekend has given us (almost) no issues. On Saturday I had driven the car about 9 miles got to my destination, locked the car, and returned about 3 hours later. When I got back to my car the horn and lights(emergency flashers) were going off as if the alarm had been triggered. My Volvo app which normally tells me if the alarm is triggered or if the doors are unlocked didn't send a message. I unlocked the car, the alarm keeps sounding, I started the car, and the alarm keeps sounding. I was able to drive the car with the horn sounding. After several minutes (10 or so) of this, the alarm finally stopped. 2 minutes later it started again (the car was running the entire time). This continued until I finally pulled the horn fuse just so I could drive home.

Got home, and locked the car, (the flashers kept going flashing intermittently (if the horn fuse was in it would have been honking). Left the car for a bit, came out with a different key (wife) switched to her profile. Went to a store and came home and the issue disappeared.

I didn't put the fuse back in. Took the car to the Volvo dealer yesterday. They looked at it and said, nothing had been triggered. Said it looked like someone might have tried to break in (small mark above passenger rear door which frankly couldn't have been there for months as I did strap a Christmas tree down pretty tight back at Christmas). He stated that I may not have reset the alarm since I wasn't using the regular key fob but was (as I have for 5 years) using the small sports fob. He put the fuse back in and said to monitor it until he can get it in for service in a week or so. That was more than 24 hours ago. About 20 minutes ago the horn and lights started sounding again.

I looked at the app. Doors are locked, "everything is fine" and the alarm is not triggered.
I pulled the fuse again.

Has anybody else ever had this experience? I am open to suggestions.

Thanks in advance.