GPT-5.5 thinking silently routed to 5.4 for 8 days

Hi Smith, since your last reply I still haven’t received any further update from the support team, and the issue remains unresolved. I’ve been completely unable to use GPT-5.5 thinking since April 29th. Every response across all conversations, devices, and new chats is generated by GPT-5.4 thinking, despite 5.5 thinking being selected. Your Help Center states that selecting Thinking means using GPT-5.5 Thinking, so I don’t understand why I am completely unable to access the model I selected. At this point I need to understand what is happening with my account. Is this a known bug, an A/B test, or some form of account-level restriction? Could you please check and confirm? Thank you.