mouseEnabled=false; not working on movieclip?

[ListlessH]

Using Animate CC, Actionscript 3 (swf and canvas).

I have a stage with many symbols.  One semi-transparent movieclip flies across the stage, covering everything, then exits.  When it flies across the stage, it interrupts any "over" states for buttons currently active, as if it's interrupting the mouse.

In the movieclip, I have a layer for actionscript with the following:

this.mouseEnabled=false;

this.mouseChildren=false;

Seemingly this does nothing.  I get the same result when publishing as a swf and HTML5 canvas.  How can I fix this?

[ClayUUID]

I just tested a movieclip containing "this.mouseEnabled = false;" on top of a button, and it worked fine.

[ListlessH]

Weird.  It's a client project under NDA so I unfortunately can't share the actual file...  Maybe a little more info will help.

I have all of these symbols in one layer.

The movieclip in question contains three layers itself - an actionscript layer, a mask layer, and the layer for the image that flies across the stage.

The mask layer is just single color shapes (not symbols).

The image layer contains a graphic symbol with a single frame.  The graphic symbol is tweened to fly across the stage.