Caused by866fcd0a09To search for strips, we do so on an `Editing` object or a `MetaStrip` object. Code from866fcd0a09got the `MetaStack` but then tried to use this directly as a `MetaStrip`. We should be getting its `parent_strip` though it seems. For reference, this is what was done prior to866fcd0a09`sequences_object = ed.meta_stack[-1]` Pull Request: https://projects.blender.org/blender/blender/pulls/146967