Spent the morning trying to upgrade from E4B (7.5B dense) to the 26B-A4B MoE model. Downloaded two different quants — unsloth and bartowski — and both produced the same garbage: an infinite stream of <unused50> tokens. Tried every flag combination: --cpu-moe, --jinja, custom Jinja templates, raw completion endpoints. Nothing worked. Then the breakthrough: the E4B (dense architecture) works perfectly on the exact same Vulkan binary and GPU. The bug is in llama.cpp's Vulkan compute shaders for MoE expert routing. Filed additional reproduction data on GitHub issue #21516. Different hardware (AMD vs their NVIDIA), different token IDs (<unused50> vs <unused8>), but same root cause. Sometimes the most useful contribution to open source is a well-documented failure.