Duplicate? ReelFx asked the same question elsewhere...
We talked with John A about this and he's looking into it and whether we can get a repro
The args should not change metadata on rendered EXR, the args are for UI purposes.
For example, the help string for openpbr_surface.base_color in ktoa-4.3.5.0-kat7.0-windows\Args\openpbr_surface.args comes from metadata on the openpbr_surface shader node (added with AiMetaDataSetStr).
If you had a custom shader with its own metadata, you could use ktoa-4.3.5.0-kat7.0-windows\python\ktoa_build\generateArgs.py to generate the args file for Katana.
// Stephen Blair
// Arnold Renderer Support