I agree with the other comments that the LKA is likely the culprit. As you approach the edge of your lane, you'll feel a slight tug.
Please note: If you don't use directionals when switching lanes, you may feel LKA more often as directionals override the LKA system. Also, on occasion it may sense a line on the road, such as a crosswalk, which may throw the system off.
Let us know if these are not the conditions you've experienced.
It's a good habit to make sure the triangle on the top center of your windshield is clean. While you're at it... also clean your grill emblem if dirty.
As a side note:
After reading the manual image above, I wouldn't have thought about turning LKA off in bad weather conditions. DOES ANYBODY ACTUALLY DO THIS?
I have had a similar purpose system - Automatic Emergency Braking (AEB), activate while approaching a crosswalk (with no pedestrians). Fortunately it was just a slight tap on the brakes accompanied with an audible warning but there were no cars or people in the area.
I'm assuming it activated because the sun was low in the sky (and bright) in front of me - which I've read can throw these systems off too.