Custom GPTs confuse any uploaded file with one from a closed session and deleted GPT?

Help me understand what’s going on here. ChatGPT will swear up and down that there is no record of an uploaded file retained in storage or memory but if I upload any spreadsheet when creating a ‘custom GPT’ and ask it what the column headers are it will list the columns from an unrelated spreadsheet that I uploaded for the first ‘custom GPT’ I created. That session was closed weeks ago and I’ve deleted all my GPTs and created a new one and it will still reference that original spreadsheet in response to any question about any .xlsx file I upload now. It appears to retain the entire contents of that file and confuses any new spreadsheet I attempt to upload with it.

This problem applies not just to ‘custom GPTs’ I’ve created but to any session with any open AI model including public ones made by chatGPT. Any model substitutes the spreadsheet I uploaded weeks ago for any .xlsx file and doubles down on the assertion when corrected.

This problem applies to other file types as well such as .ods spreadsheets and .csv files. All open AI models in any session are regurgitating the contents of a sensitive client file I uploaded weeks ago in response to questions about any file I upload now. Wtf? The TOS and privacy policy are very explicit that there is not supposed to be any record of uploaded files retained after the session is closed. How do I know it’s not randomly regurgitating my clients’ private data to other users as well?