But when I switch to cat form after that, it will show that my [Tiger's Fury] also has 3min CD, just because it's on the same spot on the bar, even tho it's not 3min, and I did not even use it yet.
My question is, is there a fix for this, without getting a different Addon?
Could you provide a download link to the CooldownCount version you are using?
According to wowace there seems to be no version tailored for 3.3.5a:
I can't recreate this on my druid with the version Oct 16, 2008 (Patch 3.0.2).
I presume your problem is either caused by CooldownCount or some ActionBar AddOn (could be a variety of AddOn's that mess with either the buttons and / or bars).
Reason for that being the following:
One has to understand how these cooldown timers work.
These AddOn's create a timer on the button as soon as the cooldown animation of it starts (API - SetCooldown - checks if it hasn't been created before).
So in your case the timer is created as soon as you use Enraged Regeneration.
Switching stances should update every button / cooldown animation causing the timer to switch from 3 minutes to [remaining cooldown time of the new spell on your bar or 0].
This does not seem to be the case.
Either CooldownCounts previous' button timer isn't hidden properly OR some ActionBar AddOn is not correctly managing stance / posession changing.
The result would be your action bar still working correctly but the buttons/tooltips are for the wrong bar.
Does this happen with only CooldownCount loaded aswell?