motion diff: amendment and nested list (dot in text)

Describe the bug
The motion diff of a motion with a nested list and a dot and an amendment with a change to second level of the
nested list is an all deleted (red) and everything new added (green).

and the amendment hasn't got a title.

How to Reproduce

1. Go the motion list in a meeting
2. Create a new motion with following text: <ul><li>Ebene 1<ul><li>Ebene 2.1</li><li>Ebene 2.2</li></ul></li></ul>
3. Create an amendment to this motion with <ul><li>Ebene 1<ul><li>Ebene 2.1 foo</li><li>Ebene 2.2</li></ul></li></ul>. The foo is the only change
4. Look at the motion detail view

Expected behavior
It should work like:
motion text: <ul><li>Ebene 1<ul><li>Ebene 2A</li><li>Ebene 2B</li></ul></li></ul>
amendment text: <ul><li>Ebene 1<ul><li>Ebene 2A foo</li><li>Ebene 2B</li></ul></li></ul>
So it should only show the foo in green (as change).

Additional context
I think it is a problem with the HTML Diff stuff

motion-txt:

<ul><li>Ebene 1<ul><li>Ebene 2.1</li><li>Ebene 2.2</li></ul></li></ul>

amendment-text

<ul><li>Ebene 1<ul><li>Ebene 2.1 foo</li><li>Ebene 2.2</li></ul></li></ul>

Start in the motion detail view and trace the HTML diff implementation used for motion amendments. Reproduce the nested-list case with a dot in the list text, then compare it with the simpler Ebene 2A/B example. Done means unchanged content remains unhighlighted, with only “foo” shown as an addition and the amendment title behavior checked.