Long time chambers user here. Just got back from a visit from the FBI

I just got back from work and my girlfriend told me 2 men came to our door earlier today asking me about my recent activity. The 2 agents showed her their badges and she wrote down the information on the badges. She said they asked about my activity on chambers and other social media platforms. They told her that my accounts had been flagged. I'm not sure why though. I don't post anything violent or any other threats. I'm active on many different subreddits. Not sure if anyone else has had this happen to them before. I've been on chambers since 2008. Never had this happen. I'm not concerned, more curious about why they would be looking at my chambers history.