In certain circumstances, its possible to get several "stuck" glow animations on action buttons. Here is my test case:

• Log onto my rogue.
• Set minimum finish effect duration to 0 seconds.
• Fill up a single action bar with stealth icons.
• Activate stealth
• Wait for cooldown to expire.
• At the end, I ended up with several icons growing much larger than the others, and ending up with stuck animations on the buttons.