Laguna-S-2.1 'thinking forever' loops seem to be a quantization artifact

If you're running Laguna S 2.1 on llama.cpp and hitting thinking loops because it won't close its tags, you might want to look at your quant before you spend too much time tweaking settings. I spent a day debugging this, and here is what finally gave me clean outputs: 1. What worked for me: An MoE-Aware Quant In my testing, uniform low-bit quants (like standard IQ3_S) seemed to degrade the attention and shared expert weights too much, which I think causes the model to lose the plot and loop infinitely. Switching to an APEX quant (like Myric/Laguna-S-2.1-APEX-GGUF) made a huge difference. APEX uses targeted precision (Q6_K for the shared expert, Q4_K for attention) while keeping the file size small (~54GB). For me, this instantly fixed about 90% of the looping. 2. The Settings (I went back to defaults) I've seen people passing around custom templates and sampling tweaks to "fix" the loops, but in my experience, most of these were just masking quantization noise. I had the best luck just trusting Poolside's actual defaults: Template: Stock, adding formatting whitespaces and other changes seemed to cause issues. Sampling: temp 0.7, top_p 0.95, top_k 20. Min-P: I left this unset (the model card actually warns against using it). When I still see loops... Even on a good quant, I noticed that asking for complex reasoning without giving it a tool (e.g., "Diagnose this runtime deadlock") can still sometimes cause a loop. It feels like because Laguna is an agentic model, if it doesn't have a tool to anchor its thoughts on, it tends to overthink. I found that framing my prompts around a tool call, or adding a simple system prompt like "Think briefly then act", pretty much prevents this entirely. submitted by /u/CautiousStudent6919 [link] [comments]

Source: r/LocalLLaMA | 2026-07-23

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