Do you ever see button functionality changing between builds?

I have a fairly complex navigation pad (a set of custom buttons that track progress and turn on and off based on that progress)

 What I'm seeing is that sometimes when I do a project preview or publish.  One of the button stops working. 

By that I mean that tt only is active at the very edge (5-6 pixels) of the button (on what appears to be the hover state because you can see the glow edge light up)

It seems like the event trap layer for the disabled state of the graphic gets  raised to the top without showing the actual image layer.  

I'm tracking about 10 variables and 20 objects on the page

The button in question has very little logic attached to it. and is infact never disabled. 

If others have seen inconsistent behavior on buttons/states, any insights would be appreciated..

Thanks

Todd