You should not apply the garbage matte to the title layer.
You have told the title layer to scroll (animate) so its logical the garbage matte will follow this instruction as well. (FWIW - scrolling or crawling a title is only some "motion presets" applied to the title you created). You can easily do the same manually to a static title.
You need to create a duplicate layer of the scene that contains your frame and apply the garbage matte to that.
You will need to work out the order of the layers.
Why your garbage matte moves with the scrolling title i do not know because mines holds still.
Try the crop effect.
Here's something that you might want to look into:
Put your "picture frame" on the Track above the Title. Use the Track Matte Keying and do a Matte (placed one Track above the "frame"), with your Scrolling Title below both.