Responses API Bugs - duplicate output messages and tool calls

[Maciej_Kiernarzycki]

Same situation here, but i have encountered that on 4.1-mini. This happens in Chat Completions API too.

[URGENT] GPT-4.1-mini consumes unknown amount of input tokens

Today I noticed a very worrying behaviour of 4.1-mini. I sent 119 input tokens, but receive almost 40x more input tokens in response usage. Two short messages and almost 5k input tokens. Response contains multiple duplicated structured outputs with the same message identifier, which also counts as output usage. This is serious issue that can cost someone in production quite a lot. To reproduce that behaviour you need to configure tools, structured output and drop a unresolvable message. Her…