If that would 'fix' the light leak , then the light leak would not just be in the image area, but also across the edge of the rebate.
It is not, so taping stuff up will do nothing.
This really looks like a hole in the shutter. I've had the notorious M5 leak (fixed by the amazing Zacks when everyone else failed!) it is does not look like this.
Holes in the shutter can be really hard to see...
I see the leak extending down into a sprocket hole, which complicate the matter somewhat.
As MattKing noted second image of negative shows light leak going into rebate section. It could still be leak through the shutter but light leaks can be quite unpredictable and hard to diagnose.
I dealt with many light leaks that couldn't be seen in normal way. Different intensity, location and shape of the leak on two images is also adding complexity.
Method of elimination is always the best. Eliminating possibilities one by one at a time. In this case it would eliminate any leaks through body and leave shutter.
Other thing that is very helpful is using few frames at a time and doing quick development in tank pulling film out and cutting. That way one roll and few hours will troubleshoot the most stubborn light leaks.
A couple of shots with body cap on will eliminate shutter. Exposing body to strobes from different angles will show leaks more easily.
My personal method in this case would be digital camera on high ISO and long exposure combined with strobe from different directions. That would save lots of time.
Checking through lens mount would resolve that side. The easies way with film is to use darkroom changing bag for testing. Elastic sleeve can be put around lens and only light is coming through the lens.
If this produces light leak, than it must be through the shutter.
So far, in my opinion, I don't think any causes are completely excluded.