I am not sure whether this is something on the CIT side or New Default+. When I rename an elytra, it instead displays as just plain green. Screenshots and logs below.

2023-07-09-1.log

I see several lines like this in the log (line 4279). However, none of the elytra that had an error matched the one I tried to use from the resource pack.

[00:40:24] [Worker-Main-182/ERROR]: {citresewn} Errored while parsing CIT: Cannot resolve path @L3 in minecraft:optifine/cit/elytras/community/0_broken_cobalt_elytra_icon.properties from file/NewDefault+v1.67[MC1.20-1.20.1].zip

The second and third screenshots are to show that the elytra is retextured correctly in my inventory, but not my player model.