The other answer is right to point out that recently done seasoning can be brown rather than black. It is still important to make sure it's not rust below a first thin nonblack layer of seasoning. You may want to scratch a little bit off and check the texture, to see if there is rust below the slick surface.
Normally such rusting shouldn't happen, but you ...
The brown stuff is presumably polymerized oil, AKA "seasoning". At sufficient thickness, it appears black (but blackness is unnecessary for it to be effective as a surface treatment). I don't see any sign of rust in those pictures.
I've seen similar things on a couple of pre-seasoned pans (one of them a Lodge). My suspicion is that the uneven heating of the pan leads the seasoning in one area to burn, while the other area completes the polymerization that began during pre-seasoning.
The number one thing that people do wrong with cast iron is worrying too much about the seasoning. ...
That is an enameled cast iron pot. I often have the same issue and find that it fairly easily comes off using a green 3M nylon scrub, a little dish soap and some elbow grease. If necessary you can also apply some baking powder or Bar Keeper's Friend.
It shouldn't take too much effort to get it off.
I bought shelf liner (non sticking), turned the pan upside down and traced the pattern of the pan to about 1-2 inches larger and placed it in the cooled bottom of the pans. I have not had any problems of rusting ever.