Movie Clip object restarts itself when root moves it

[ I’ve had a hard time trying to find any information on this by searching - the keywords are so generic, I get a lot of results but nothing that answers my question. ]

I’m working on a website design and can’t figure something out…

I have a movie-clip object in my root timeline - a slide-out menu. The root tweens the clip into place, then the clip becomes active (via some crafty variable coding on my part). Mouseover will slide out the menu, mouseout will close it. Clicking on a menu item will jump down the clip timeline to play a different ending (one without a layer becoming opaque, but the menu still rolls up).

When there’s a click, once the clip hits its end frame, there’s 2 actions - a stop action and a _root.gotoandplay action for the root to then tween the clip over to the side.

My problem is that when the root tweens the clip, the clip doesn’t stay at its end stop frame, it seems to reset itself to frame 1.

Why is it resetting itself? In theory, if I set the menu-open as the last frame of that clip, shouldn’t it stay open when the command is sent to the root for it to perform the tween? Or is it the keyframe resetting the movie clip object (which is instance-named)?

I can provide more details if needed - or even post the site.