833 OD sticking in 4th, chipped synchro

I can tell you exactly why that is happening. The slider is over-shifting.
And this happens when one or more of the following conditions exist;
1) the brass ring is sitting too far down on the brake-cone, or
2) one of the energizer springs is either broken or out of index, or
3) The input gear is too far towards the engine, or
4) the mainshaft is too far toward the rear end
5) the shift interlock levers are worn, or
6) the wrong slider has been installed, or
7) the wrong style brass ring has been installed
8) the cover is not properly located

Ima going with numbers 7 and 1, because
that ring does NOT match the slider-hub. The brass is a pre-72 type while the hub is a 72-up style
Take a look at the other brass and MAYBE you can see what I mean.
Edit; I added #8