Problems on the FN2 are quite "commonly" found within 3rd gear (in the previous model EP3 it was 2nd gear). The appropriate procedure for this is to replace the synchros, there is an official Honda Service Manual for this one, which replaces 3rd and 4th gear synchro, maybe this solves the problem? However I remain skeptical, whereas the 09 models would already been fitted with these updated synchros. Second, your problem indeed seems an isolated problem, I also never heard of a problem in 4th gear, let alone the vibration issue you describe.It's noticable under acelleration, sometimes it's bad other times it's very slight.
I'm not happy.
So I'm guessing your type r does not do it.
Same with my 4th! thought it was me imagining things but its only a slight vibration with me-when cold and when your hand is resting on the gear stick. When warm it is fine and all other gears are fine all the time too. dont think you have anything to worry about unless its actually popping outWhen I'm in forth gear the gear stick stutters, jerks forward and it's about to pop out from lowish revs, normal range it just vibrates when I touch it. All other gears don't do it.