KZ400 downshift from 5th difficulty

My '76 KZ400D shifts freely up and down between all gearings except for coming down from 5th to 4th. I opened everything up and was able to recreate the issue when rotating the drive/output shafts by hand. As the 5th gear shifted over during the downshift movement, the teeth on the gear would sometimes be out of alignment from where they need to sit into the 2nd gear. With just a little play given to the shaft they can eventually find alignment to complete the downshift. This seems to align with my riding experience which requires a few taps to the shift peddle most of the time before it finds that 4th gear configuration.

Ultimately it isn't the worst thing in the world because I can get out of 5th with some light care to tap it into 4th (I'm being careful to not jam on the peddle because it looks like the previous owner may have been doing that, which necessitated replacing the shift shaft that had warped at the shift peddle end). I'm mostly curious if this is a common issue with a known adjustment/fix. Going to keep riding the thing, annoyances be damned!

Did you check the shift fork for straightness and wear? A bent fork can cause that, and I suspect a badly worn one could, too. If the po managed to bend the rod, I would not be surprised at all if other things were bent. He bent rod could also cause unusual wear on the forks.

I thought long and hard about responding, but I have never worked on the trans for your year and model, so instead of showing my lack or knowledge I chose to be quite. I am sure there are many here, at least it appears to me that have this knowledge,  I do agree with what Texas said. I would look at the forks, the shift drum and it location/settings.  There could well be issues with the actual gears but moving them appears to be controlled by the forks and the shift drum. At least that is my limited understanding.  I guess a question I would ask, what happens if instead of going from 5th to 4th, you go from 5th and 3rd or lower does it work as it supposed to ?