After seeing it mentioned here a few times, out of curiosity, I decided to look at my records on https://i94.cbp.dhs.gov/
After I saw this:
Class of Admission :WB
I looked around and saw that this means that I was admitted as a Temporary Business Visitor.
The thing is that I never went to do business, only to visit in-laws, and I never stated anything different than that.
Is there any point in trying to figure out why my Class of Admission is that? Or trying to getting it rectified?
Me and my SO had an issue two trips ago when I packed one item that I did not know was forbidden and got confiscated on arrival. This probably has flagged us as we're travelling together, but would that be a reasonable cause to be classified as "business" traveler?
So far we've never been denied entry, I always apply for the ESTA on time, and it is still valid and never got refused. My SO is a US-citizen.