Light flare or diffraction?

Here are two pinhole photos, taken one after the other, same place, same exposure time, same film, HP5.

The first one is with an Ondu 6x12, the second with a film cannister pinhole made by me.

The position of the sun is clearly seen in the photo taken with the Ondu.

My question is, are the bright light beams clearly present in the second photo, taken with the 35mm film cannister pinhole, light flare, or diffraction? Or more sensibly perhaps, should I be asking if the light streaks are caused by diffraction, rather than flare? So far I've been telling them those streaks are caused by the light bouncing around in the film cannister, so far that's been unquestioned but is even that accurate?

I hope what I am asking makes sense, thank you. I would like to know how to explain the effect seen in the image to people who question it. Thanks in advance for any help.

Diffraction causes that overall fuzzy look. The white areas look light struck from a light leak somewhere. Where are the sprocket holes on the second one? Do you have a print showing the entire negative or can you show a scan of the negative, that can help figure it out.
I'm not sure how a lensless system could have lens flare.

It could also be light reflected from shiny edges of the pinhole or an unblackened interior of the film canister.

I can't scan a strip of negative and show the sprocket holes, as they are covered over by the scanner's film holder. When I printed this negative, I cropped the sprocket holes out when framing - they distract from the image.

I have made other photos with the same film cannister and not had the effect of the light streaks, so it is not a light leak.
And the brass shim I used to make the pinhole is darkened down on the inside, to help prevent any problems. The film cannister and lid is all black, completely light tight.

I'm not saying this is a problem related to the film cannister, as I have used the same one for other photos taken under different lighting conditions, without this sort of effect.

Oh edited again, to add that I like the effect of the light streaks, that is not the problem. I just want to explain when people ask what they are, and be relatively accurate in what I tell them.

The bright white areas are lensless flare. Black plastic film canisters are fairly shiny compared to the flat black paint used on the inside of a traditional camera. You have the sun light entering the pinhole and bouncing around inside the canister, even though the sun is outside the image area. In a traditional lens this might cause flare, or it might be vignetted/baffled by the design of the lens; the pinhole doesn't have baffles. It doesn't occur in other images because it depends on the sun position.

The white parts that look like rays coming from the sun position could conceivably be reflections off or diffraction by the irregularities in the edges of the pinhole.

Those are all classic examples of stray light artifacts.

Reddesert and Nodda Duma, thank you both for your replies, they are very helpful.

One thing is, even though the black plastic film cannister is somewhat shiny, the plastic is mostly covered by the strip of film, which is 7cm long and comes to within 5mm of the pinhole itself. The plastic lid is the only part that is uncovered, so perhaps reflection from that is coming into play? Or could the reflective nature of the film base itself be part of what is causing these effects?

I really like the description of them as stray light artifacts. I had been thinking of them as artifacts, so there at least, I was heading (stumbling?) in the right direction. That is also the simplest explanation to give, so thank you for that.

Is it feasible that the water came into play with reflecting the sunlight and thus contribute to the stray light artifacts?

Wouldn’t be able to say exactly what the stray light paths are without analyzing the system. I would, however, guess a glint path at or near the pinhole. The symmetry tells me the light is coming in through the front so if I were doing a stray light analysis I’d start there (like I do with most designs).