iris-mc1.17-1.1.3.jar + fabrication-1.17-2.3.0.jar + shaders on = o no
issue occurs with any version combination of iris and fabrication, tested with the last 3 versions of each

enabled (any shaderpack)

disabled

either "trivial to fix" or "literally impossible to fix" but i am unfortunately too lazy to figure out how to run renderdoc on a java program, apologies

...Does Iris not implement the white part of the overlay texture?

This no longer seems to occur. Assuming this was fixed on Iris' end.