---
format: "aidr-story-markdown/v1"
id: "2ee78869ffac228a3a368d95ca2929988234fcf9f9e38a8d0f92156d44f47776"
canonical_url: "https://aidr.today/2ee78869?lang=en"
title: "Fireworks AI Fixes GLM-5.3-Flash Overthinking Issue in 2 Day Launch Delay"
lang: "en"
requested_lang: "en"
available_langs: ["en","vi"]
translation_fallback: null
fallback_fields: []
published_at: "2026-08-30T08:37:30.000Z"
category: "Models"
topics: ["inference","llm","benchmark","open-source","reasoning"]
source_urls: ["https://huggingnews.com/ai/update-fireworks-ai-fixes-glm-53-flash-overthinking-issue-in-2-day-launc-3f64a5a0","https://x.com/vllm_project/status/2093901485172285804","https://x.com/sgl_project/status/2093919236506923347","https://x.com/morganlinton/status/2093874550253691293","https://huggingnews.com/ai/zai-fixes-glm-53-flash-reasoning-bug-after-fireworks-ai-delays-launch-160b8313"]
summary: "The company pushed back the release of GLM-5.3-Flash to address a benchmark discrepancy that caused reasoning times to be twice as long on AIME and GPQA tests. An investigation conducted with vLLM and SGLang found that open-source engines produced reasoning that exceeded the length of the Z.ai API, which threatened token efficiency and model quality. Z.ai issued a rapid API update to standardize reasoning lengths across providers and ensure consistency. Fireworks AI opted for a Day 2 launch rather than a Day 0 release to prevent users from wasting tokens on overthinking behaviors that could have increased operational costs."
---

# Fireworks AI Fixes GLM\-5\.3\-Flash Overthinking Issue in 2 Day Launch Delay

> [Open the canonical story](<https://aidr.today/2ee78869?lang=en>)

**Published:** 2026-08-30T08:37:30.000Z
**Category:** Models
**Topics:** inference, llm, benchmark, open\-source, reasoning

## Summary

The company pushed back the release of GLM\-5\.3\-Flash to address a benchmark discrepancy that caused reasoning times to be twice as long on AIME and GPQA tests\. An investigation conducted with vLLM and SGLang found that open\-source engines produced reasoning that exceeded the length of the Z\.ai API, which threatened token efficiency and model quality\. Z\.ai issued a rapid API update to standardize reasoning lengths across providers and ensure consistency\. Fireworks AI opted for a Day 2 launch rather than a Day 0 release to prevent users from wasting tokens on overthinking behaviors that could have increased operational costs\.

## Sources

- [Story source](<https://huggingnews.com/ai/update-fireworks-ai-fixes-glm-53-flash-overthinking-issue-in-2-day-launc-3f64a5a0>)
- [Story source](<https://x.com/vllm_project/status/2093901485172285804>)
- [Supporting source](<https://x.com/sgl_project/status/2093919236506923347>)
- [Supporting source](<https://x.com/morganlinton/status/2093874550253691293>)
- [Story source](<https://huggingnews.com/ai/zai-fixes-glm-53-flash-reasoning-bug-after-fireworks-ai-delays-launch-160b8313>)