Strange low contrast in middle of negative Fuji gsw690ii

[Filmandfile]

Picked up a new to me Fuji gsw690ii, on first inspection the negs that came out of it were good but after scanning (which I’ve attempted with different light sources and different cameras) I’ve noticed a strange low contrast circle in the middle, it seems to be around the middle of the roll on both rolls I’ve shot with it so far, any ideas? I’ve edited the image to accentuate problem. Some of the images are perfect

 

[Chuck1]

Is the lens hazy?

 

[Filmandfile]

Is the lens hazy?

Can’t see any sign of haze

 

[Craig]

Flare perhaps?

Try setting the shutter to T, open the shutter and then shine a flashlight through the lens and look at it backlit. It's amazing how a lens that looks good will look hazy when the light is shone through it.