My universal custom instruction includes a provision to always respond in British English. See this below.
This custom instruction does not follow through to the naming of Assistant threads. This happens with a number of models. See below. Interestingly, the threads' subtitles do follow the custom instruction.
ChatGPT
Claude
Gemini
Grok
Mistral
Qwen
When deleting the custom instruction and leaving it blank, and then inserting it into the prompt instead, this issue does not arise.
See two examples below.
Claude
Gemini
