What did I get wrong about the Hasselblad A12 light seal installation for my 500C?

[Certain Exposures]

Hi folks. I could use some of your advice. What did I get wrong about the Hasselblad A12 light seal installation for my 500C? I added a fresh set of dark slide seals. However, there's still a light leak. It's not in every frame. I followed the instructions in these videos: 1, 2.​

Someone on Reddit claims there are additional light seals that could require replacement. I have not run into information about these additional light seals yet. Do any of you have information about them?

Thanks in advance for any insight you may have.

Test frame with a light leak circled in yellow:

Pictures of my light seal replacement job:



Suggestion that there are inner seals that could require replacement:

 

[Don_ih]

22, 25, 28, 35 are also light seals. Did you replace 41? You have the foam sitting in 37? The light seal at the dark slide is the one that suffers the most, since the slide gets put in and removed. The other seals likely have probably fossilized, but they're also possibly still doing their job if the back has never been taken apart. The light leak you have looks like it's coming from the dark slide. The slot 41 fits into needs to be cleaned out completely before replacing it, or it can get caught by the dark slide and pushed out. And you fit the foam into 37, right?

People like to stand at their pulpit and wag their finger. But the fact is, most of the time a Hasselblad light leak is fixed by buying one of those cheap kits. Take it apart again and see if anything looks wrong.

 

[OAPOli]

I had a similar light leak on my back. It's not caused by the dark slide seals but most likely by the seals no. 28 outlined by @Don_ih. I think I changed 22 as well. No tutorials online but it wasn't very difficult.