The most likely cause is very underexposed negatives that the lab scanner had to push hard to recover. With color negative film, underexposure often leads to thin negatives and a greenish cast when scanned or printed. If the scanner applies a lot of gain to pull detail out of a very dark frame, artifacts such as vertical lines or streaking can appear.

So the lines are probably from the scanning/recovery process rather than a normal characteristic of the camera itself. It’s less likely—but still possible—that there is physical damage or streaking on the film.

A good next step is to inspect the actual negatives with a loupe or magnifier. If you don’t see the lines on the film, that strongly suggests a scanning issue. If the negatives look extremely thin/almost transparent, that supports underexposure or underdevelopment as the root problem.

In short: the camera is probably not the issue; thin negatives plus aggressive lab scanning is the most likely explanation.