Interesting. Are those dark bits on the film-edges or are they the inter-frame edges? I originally assumed they were edges and that this is 645, but the exposure printing in there (and lack of film-ID printing) is confusing and makes me think this is maybe your 690, but this doesn't look wide enough to be 45mm on 6x9 and if that 003-14 means "frame 14" then has to be the 645...
Anyway, the weird thing is that the exposure-printing seems to have been developed nicely despite the image near there being darkened. And it seems to go towards a middle-grey rather than black; see in the tree at upper-left it's no darker than at the right.
Is there any chance you accidentally got some gloved fingers in front of the lens or something? What do the negs look like, do they have any slight milkiness or brown staining?