Placeholder Icon doesn't appear (even if you set it as the icon) on blocks after adding wagtail_react_streamfield (in general)

[ZackPlauche]

Before adding 'wagtail_react_streamfield' to settings.py:

After adding 'wagtail_react_streamfield' to settings.py (above admin & images like it says in the docs):

Only one of the placeholder icon blocks has closed=True, but both aren't working.

(Also as a side note, the layout of the green plus icons is different from the pictures in the README)

I'm using Wagtail version 2.12

[ZackPlauche]

Same with 'clipboard-list'