When you open the PDF, your local PDF viewer scans your operating system for a font family named "CID Font F1."
While the CID architecture is a marvel of engineering, its implementation can break down, leading to three common scenarios: 1. Garbled Text or "ToUnicode" Mapping Failures
The most effective solution is proactive prevention.
Try opening the file in a different viewer like macOS Preview and re-exporting it as a PDF.