I just went into beta features, enabled it and then immediately started writing my custom instruction. A few minutes later I tried to save the instruction and I received an error. I then refreshed the page, and discovered neither the beta option toggle nor the custom instructions panel were available. I live in Australia (I noticed it's not available in the EU or UK) and I wonder if we can't get it here in Australia or they have pulled the feature for now?

Also, I just noticed that my chats are following my custom instructions, even though the settings panel is no longer there.