Another counter-example is Phags Pa Script.
https://en.wikipedia.org/wiki/%CA%BCPhags-pa_script
Explain. The wiki you linked to specifically states that it is descended from Tibetan script, which is in turn descended from Proto-Sinaitic script.
alt Hacker News
Explain. The wiki you linked to specifically states that it is descended from Tibetan script, which is in turn descended from Proto-Sinaitic script.