This works fine, I just re-tested from 3 different apps - TextEdit, Bike, and Drafts. I’ve included the Drafts test here - copying the contents in a text editor, and then pasting to your open Tinderbox window should give you the result you seek.
Where is your source text from, and is it some form of markdown/html etc?
Make a note. In its text area, type a simple outline:
able
1
2
baker
1
2
2a
3
Copy that outline to the clipboard
Click in the outline view
Paste
I get a container Imported outline that holds the outline.
If the text is a simply a series of lines — not a tab-indented outline — Tinderbox assumes that it’s not an outline at all, but some text that contains multiple paragraphs. It extracts the first paragraph as the title, and places everything in the text.
I have to trouble imagining writing a list in the text, and later deciding to break out that list as a set of outline elements. It sounds like you’re doing this frequently: might it be simpler to switch over to the outline pane and make your list? Perhaps more detail on the goal would help…