That's a good catch - the UI shader in specific is the cause for the shader rework as it has another edge case issue.
Surely enough, swapping out the shader with unity's default shader removes the two extra drawcalls, so it looks like the shader is the cause.
If you want to use the shader I just used, it's "GUI/Text Shader" in Unity. The new shaders will be built to work similarly to that one so it should be compatible! The only thing its missing from the future updated shaders are the dropshadow/outline effects.