An Audit of 443 GGUF Quants Found 64 That Cannot Be the Quant Their Filename Claims

r/LocalLLaMA·high signalXBlueskyLinkedInCopy link

A builder audited 443 GGUF quantizations across 25 Hugging Face repos and found 64 where the file is not the type its name advertises: k-quants and i-quants need the first tensor dimension divisible by 256, and when it is not, llama-quantize silently substitutes a compatible 32-block type (often IQ4_NL or Q4_0) landing around 4.5 bpw while the filename, model card and metadata all still say IQ2_XXS. On Nemotron-3.5-Lightning all four IQ2 rungs are the same 4.58 bpw file under four different names, and two independent uploaders reproduced it, confirming the tooling rather than the uploader is at fault. The behavior has been in llama.cpp since PR #3747 in 2023; the warning only goes to the quantize log, which downloaders never see.