🐛 bug: GPT-5 cannot read some PDFs with background and/or non-black text colors.

[danilvalov]

Description

If I try to attach PDF files with background and/or non-black text colors then AI cannot read it.
If I use the ChatGPT app, it works without any problems with this PDF.
If I use a different PDF with the classic style (white background, black text color), it works without any problems.

Steps to reproduce

0. Use GPT 5, GPT 5 Nano, GPT 5.1
1. Attach this PDF to your message: AI Benefits for Users.pdf
2. Ask Mattermost AI to generate a summary for this presentation

My result