Error 400 when searching the internet

## Describe the bug

When gpt-oss-20-Q8_0 uses the search tool the chat sometimes suddenly stops and a red message displays "An error has occurred". The developer tools shows: Failed to load resource: the server responded with a status of 400 (Bad Request) http://127.0.0.1:39100/v1/chat/completions

The model runs on Intel Arc B580.

## Environment:

- OS: Windows11
- GPU: Intel Arc B580
- CPU: AMD Ryzen 5 7700
- Version: v3.1.2 hot fix 3

Reproduce the failure with gpt-oss-20-Q8_0 and the search tool on Windows 11 with an Intel Arc B580. Start by inspecting the failing request to http://127.0.0.1:39100/v1/chat/completions in the developer tools and compare it with a successful chat request. Done means searches complete without the 400 response or the generic error message.

Written by the indexing model from the issue text.