Hi everyone,
I'm relatively new to film photography and so far I'm loving it. Over the weekend I tried out an old Nikon EM camera and on some images I got a weird overexposed strip. I attached two images to show you what it looks like. The images weren't important, so no big deal. However, I'm really interested to learn what exactly went wrong.

Here's what I know:
1. It's not on every frame, just on 4 or 5 frames of the film.
2. It's always located on the same side/position of the affected frames.
3. All affected shots were made outdoor at maybe 0C/32F temperature.
4. Of course it's on the negatives, too. So no error at scanning the negatives.
5. I used Agfaphoto APX100 (the cheapest I could get my hands an for testing out the cam), Kodak HC-110, Adostop, Tetenal.

Number 1&2 make me think that there's something wrong with the camera. However, maybe one of you much more experienced guys can help me out here?

best regards,

edit: I notice the attached images were rotated after uploading them. The first images is upside down. So the strips are always located on the 'shutter-side' of the camera(were I grip my right hand onto ).