OpenAI Evals Bug Unknown Parameter

I’m seeing this error as well. I’m using Dashboard evals only — not the API/SDK directly.

Setup:

• New eval created from scratch in the OpenAI Platform Dashboard
• CSV upload as test data
• “Generate new responses” enabled
• Text columns only; no image columns
• No “Import as responses” selected
• Simple run with a developer/user prompt
• Semantic similarity grader
• I’ve tried recreating the eval and simplifying the CSV/prompt

The error appears when trying to run/review the eval:

Unknown parameter: data_source.sampling_params.text.verbosity

I did not intentionally set a verbosity parameter anywhere in the UI. It looks like the Dashboard may be injecting data_source.sampling_params.text.verbosity into the eval run config, but that path is not accepted by the current Evals API surface.