Matk seems to go up but there seems to be no difference in attack or actually damage delivered.
Well, you know MATK works off of a min~max dynamic, right? You're not always going to deliver max magical damage.
If you see in your stat window that the MATK goes up and down when they are equipped and unequipped then I'd say they work. 
Sorry maybe I was unclear, I meant matk goes up but "attack" ie physical attack doesn't change nor is there an increase in damage when attacking physically.
Is there supposed to be an increase in ATK with those? I dunno the specs.
Should be +4% ATK as well
Checked item script. Bunny Earplugs uses the same script as the following items for "bAtkRate":
-diabolous robes
-diabolous armoor
-+7 or higher ribbon hat/maiden hat
-and tons of battleground items
Of all those things, maiden hat is the oldest and first to use this script. I tried it myself on HP (I have the hat but I never looked at the Atk part since... it's not useful to me heh) and indeed the bAtkRate command is totally busted.
Add all of those items to the list of unfixables until svn update heh.
(GM can bypass this with the "old method" of how The Sign handled it: we can just say 3% bonus attack damage to all boss AND all non-boss types, and that'll *almost* be the same as 3% bonus attack. Unfortunately, this means that whitesmith and ninja and any other class with melee skills that don't work off % cards and demand direct +ATK will not benefit from the rabbit earplugs. However, that is the best and closest fix you can pull off in this svn.)
:x So...fix is pretty much a long way off and we'd be better off assuming it won't happen?
If you want the real fix (aka, you play whitesmith/physical ninja for example), yes you can pretend that it won't happen in a day.
If you are satisfied with the bypass solution, then GMs can use bonus2 bAddRace,RC_NonBoss,4; bonus2 bAddRace,RC_Boss,4; (copy/pasted from The Sign with numbers changed) so that is just a quick copy/paste edit along with a reboot. That type of fix can be delivered in a much faster time.
Why pretend when I'm guessing we won't get a reboot until Thursday? :D
Ofc, even if you give them the code, they'll claim that it needs weeks and weeks of testing, then do nothing about it for a long period of time until the issue rises again, then claim that they have had and still have "too much on their plates" and dismiss the idea until it's brought up again.