It is impossible to drag cursor to the beginning of the line in Live preview if the line starts with narrow character: I (uppercase i), l (lowercase L) or, say, | (vertical line).
Interesting, that this issue is not reproducible if you put a header somewhere it the note.
Here is a video.
Obsidian iOS, 1.5.8 (126)
iPadOS 15.8.1
ios 17.3.1