Out of the loop here. What did Google and unsloth and llama do to mutilate Gemma? I can understand Google shenanigans but llama and gunsmith is kind of surprising.

Google provided incorrect settings and an imperfect template.

Unsloth modified the template and then finetuned their own version of the model to optimize for some benchmarks as a means of validating quants.

Google and Llama.cpp then adopt template changes by default, so anyone downloading the new model or even using the original model will now automatically be using it incorrectly.

Llama.cpp also uses the same inference setting defaults regardless which version of the model you use and some settings are simply defaults it uses for all models.

Then even if you account for all of these, you have to be using Gemma 4 itself correctly, which many people do not.

All of these little changes and inconsistencies hurt some of the model's original capabilities. Even if you go directly to Google's repo and download the full float 16 weights with the template they have there now, you cannot simply assume you're getting the best results.