Thanks, I had problems with this too. Those are really helpful tips..
I suppose it would be helpful to explain why I made those guesses? :salute:
Since it's only the first few frames, it means the light got to the film while it was rolled up, and only to the edges, probably where it passes through one layer and maybe some sprocket holes. That's why you would have the red dots.
When the film is in the felt slot, it closed tight against it, but at the edges, there's going to be a tiny gap, before the felt seals again. That's where light is most likely to leak in.
When you consider that it takes 1/1000th of a second to take a photo, through a tiny hole in the iris, any stray light, leaking in, will make it's mark pretty easily.
I'd say it happened loading the camera or before you loaded the film, while it was just sitting with the leader sticking out. Carrying around film, outside of the plastic container, before or after exposure can let light leak in.
Have an example? Then it would be easier to make a guess.
By the way, it's not that uncommon. Old double 8 movie film, you didn't have a canister, the head and tail of every roll had burned out areas from flipping the film.
That's why I wrote that if you can't go inside or someplace out of the Sun, turn your back to the Sun and load in your own shadow.
