Bug description
When editing sign text, the sign uses the custom model defined by sign.jem, this is in contrast to Optifine which uses the vanilla model inside the GUI.

Resourcepack example
sign-example.zip

Screenshots
Optifine:

EMF:

System

• Minecraft Version: 1.20.2
• EMF version: 1.2
• ETF version: 5.0

Additional context
Notably ETF uses the vanilla texture and not the custom one

This appears to be fixed in the latest version, which is great!
One thing to note is there is no apparent way to actually change the sign gui texture or model (unlike the hanging sign) which could be an ETF/EMF exclusive feature opportunity (low priority of course)

That is a difference, though i don't see it as much of a problem.
is it causing any issues?

can you describe the additional context part a bit more?

It doesn't really bother me, the only thing thats a bit weird is that ETF uses the vanilla texture, so you get a broken model.
I'm making a resource pack thats pixel consistent, and I'm sure there will be a workaround, so this is quite unimportant to me, just thought I would point it out.