While F1Normal is a ghost, legitimate CID-keyed fonts (like for Japanese or Chinese) are available. If your actual need is for a professional CID font:
If you're unable to find a free download of the CIDFont F1Normal font or prefer to use an alternative font, there are several options available. Some popular alternatives include: cidfont f1normal font free download work
To summarize, here is your step-by-step checklist to resolve this issue today: While F1Normal is a ghost, legitimate CID-keyed fonts
Select the text blocks with "strange symbols" and manually change the font to a standard one like Myriad Pro Identify via Properties: In Acrobat, go to File > Properties > Fonts While F1Normal is a ghost