Just got back home. Didn't see anything on the front but didn't even think of back!
I won't ride it until I've taken the rear wheel off and inspected it and the frame minutely. If I find nothing there I will return to the headset. Hopefully it's something small.
I did check the headset with a Park 32mm wrench and it was tight. If the headset tightened I am at loss as to why it self tightened since it was tightened last time I checked the stem and seatpost to see they were greased and came free and I've ridden it perhaps 500km since without issues. I would've hand tightened the stem bolt using an allen key but that shouldn't be the issue.
Perhaps this is sign and I'd better just rebuild it now and not wait for winter.
I will post what the cause is when I find it.