Problem parsing thinking tokens on Openwebui with qwen3.6 on LM Studio

Reddit r/LocalLLaMA / 4/18/2026

💬 OpinionDeveloper Stack & InfrastructureTools & Practical Usage

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Key Points

A user reports that when running Qwen3.6-35B-a3b on LM Studio with OpenWebUI (with “preserve thinking” enabled), the output parsing breaks about 30% of the time if the reasoning text contains single or double quotes.
When the issue occurs, the model starts treating the remainder of the reasoning section as normal output, which can also interfere with the correctness of tool calls.
The tool-call flow may fail and the response can terminate prematurely with no further output tokens.
The user notes the problem did not occur with Qwen3.5 and asks whether others are seeing similar parsing/tokenization issues in this setup.

I'm having this issue that I didn't have with qwen3.5, where if there are quotes (") or single quotes (') on the reasoning part of the output, it starts printing the rest as regular output (not always though. It happens 30% of the time)

This also breaks tool calls sometimes, and the response just stops with no output tokens.

I'm hosting qwen3.6-35b-a3b on LM studio windows, on an RTX5090, with recommended inference settings, "preserve thinking" enabled (disabling it doesn't help). On OpenWebUI side, "native functions" is enabled.

Is anyone having similar issues?

submitted by /u/luckyj
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