Qwen3.6-27B: NVFP4/FP8 agent loops vs flawless BF16. Config or quant issue?

Hi everyone, I'm trying to determine if I'm dealing with a misconfiguration in my stack or if this is an inherent limitation of current quantization methods for agentic workflows. I recently set up a dedicated rig with an RTX PRO 6000 Blackwell and have been benchmarking Qwen3.6-27B , but I'm hitting severe reliability issues with quantized models that don't exist in BF16. Hardware & Software Stack