manual tranny: reverse only engages intermittently

[ACBarnett]

so my manual transmission 9-5 has developed this problem where reverse engages only intermittently, usually when the car is rolling backwards. Otherwise it the stick won't move into the gate, and it feels like something is blocking it. When it does engage it does so smoothly and, and pushing the lever into 5th to re-align the dog teeth doesen't do anything (I'm guessing the shafts are paired 1st-2nd, 3rd-4th, and 5th-reverse, and when one of the first 4 doesen't engage moving it into the opposite gate always fixes it). Does this sound like a transmission issue or a shift linkage issue?

[Raven18940]

Given the placement of reverse (way to the right of all the other gears) I'm inclined to say linkage alignment issue.