Just bought a Fujian CCTV 35mm lens - is there a problem with it?

I assume You use some kind of adapter for it (Cmount?)? If so, perhaps it is not fiting the camera and/or the lens properly? If ths lens mount was changed to be E-mount from the beginning, perhaps it leaks some light somewhere? You could try to wrap something around it and try to see if it gets better. If not - seems like some flaw in the internal optics (I guess you don't have some pink foil on your lens )