Quote Originally Posted by N_R_D
If the instance is on say Layer 8, and you add a keyframe, that instance will be in that keyframe with the instance name intact.
Only if that instance was present in the previous keyframe. I've finally narrowed down my problem and have a workable solution. Earlier I failed to mention that in parts of my timeline I remove the button instances. If the mc lands on a keyframe that does not have the instance, then travels farther down the timeline and lands on a keyframe that does have the instance, the Actionscript at that subsequent keyframe does not work unless the new instance has a unique name.

So for example
Frame1
bio_btn

Frame20 //no bio_btn

Frame50
bio_btn

If the mc landed on Frame20 where the bio_btn does not exist and there was a keyframe between Frame1 and Frame20, then the ActionScript in Frame50 referencing bio_btn would not work if there was a keyframe between Frame20 and Frame50 until bio_btn in Frame50 was renamed to bio1_btn (something unique).

I am pretty certain by now. I researched everything I could find including Adobe's LiveDocs and it appears Flash has always had problems with keyframes and persistent instance names. My workaround is to make a new instance name incremented by 1 after any keyframes within which the instance does not exist. Everything in my project is working fine now.