Gemma:26b thinking issue in openWebUI

This r/ollama thread discusses user-reported issues with the Gemma 4 26B (a Mixture of Experts model) and its "thinking" mode when used through Open WebUI. Key problems include the model getting stuck indefinitely in the "thinking" state within Open WebUI, as well as a known bug where the model returns a completely empty response when the system prompt exceeds roughly 500 characters . Thinking mode is controlled via a <|think|> token at the start of the system prompt, and can be disabled by removing it , though Open WebUI's handling of this token and the model's reasoning output appears to be a source of the reported friction.

Source: r/ollama | 2026-04-13