What a blast from the past. Kodak released Kodacolor II to coincide with the launch of the 110 pocket Instamatic camera (a very small neg not unlike a 16mm frame) and then later made it in all other sizes. I have hundreds of 35mm negs that look like this and many are worse. They didn't look like that when first processed although the mask was much naturally more brown than the bright orange of the earlier Kodacolor X film. It was clearly an early chemistry/lab problem with C41 that was eventually sorted. The ones I have were all lab processed and some are worse than others and I have some that are totally normal. I don't know if 110 negs were similarly affected because I did not own a 110 camera. Some of these negs became quite difficult to print well over time.
BTW 35mm film is commonly cut into six strips of 6 negs - bit of a pain if you squeeze 37 or 38 onto a roll. OzJohn