Glyphs in screen

Hello,

Screen won't render certain glyphs for me, how can I go about 
troubleshooting this?

I'm using iTerm2 on a Mac, with screen:
Screen version 4.99.0 (build on Jan 10 2020 20:24:57)
(I built it from the git source in January).

But the fonts I have configured in my iTerm2 are from the NerdFonts site.
What's weird is that Screen renders certain glyphs but not others.
Here is an image.

https://postimg.cc/SnZcDYpx

The top pane is a regular iTerm2 shell (you can see the Python snake 
glyph).
The bottom pane is screen. The AWS cloud glyph renders correctly in both 
terminals but the Python snake does not render in screen.
(Similarly the Git Branch glyph also does not render in screen.)

I also have the following env set:
LANG=en_US.UTF-8
LC_TERMINAL=iTerm2
LC_TERMINAL_VERSION=3.3.12
TERM=xterm-256color

thanks!
Mansoor