Theme asset file not rendering in extension app block

Recently I saw issue in liquid app block, in which theme asset file not rendering.
default theme liquid box rendering same code : https://imagelink.click/OLywoR.png
But in custom liquid app block not rendering same code : https://imagelink.click/BtQhZq.png

Hi Usman,

If you do a diffcheck on the code for the two blocks what is the difference?

Can you explain me the way of rendering theme snippets and assets file in app block liquid using liquid formate?