My customized GPT decided to stop reading pdf

My custom GPT (which I built for my dissertation as an academic mentor) does not read anymore the papers that I upload in the discussions with the paperclip symbol.

Not only does it not read it but it summarizes every single time an article I uploaded in the instruction section of the GPT which has absolutely nothing to do with it. Every new PDF gets the same treatment: GPT PhD mentors feeds me back a summary of the same odd article in the instruction. :unamused:

Has anyone experienced this? Or something similar?