Yes, it’s the blocking crease. You can see it on the photos below (I switched the boots in the second picture to show it’s not just the angle of the light)
View attachment 1220975
View attachment 1220974
Eh, yeah the toecap worries me, I would get a second opinion on that or just say you're not comfortable with it and you'd like to exchange. Behind the toecap is fine but as the toecap doesn't really change shape I'm dubious if that will go away properly.