We also have experienced the same issue with Arial Fonts being Jumbled. It has only effected some of our PC's where as most PC's in our organization can render the Text Correctly.
As a work around Solution we have been saving the "PDF" as "PDF (embedded fonts)" version and this seems to have rectified the problem on the PC's that do have the issue.
This issue started last week on the 15/11/2017. The PDF files that are being jumbled we noticed have the following Text File Properties "Encoding: Itendity -H
You can check this by going into Adobe DC, File > Properites > Fonts
On the Same PC that is effected with Arial Font, we noticed Arial Font's do work when the encoding type is set to "Ansi" and Type is: TryType rather than TrueType (CID)
Not sure if anyone else is having issues with Arial Fonts and with this particular encoding, however any light shed on the issue would greatly be appreciated.
Same problem, did either of you ever get this resolved?
I have also noticed that our Word-to-PDF templates have the CID (non-ANSI) fonts, and I'm thinking this is also a root cause. We also import files from other sources, that I have seen have obscure fonts, that have a knock-on effect you explain. If both files can be checked before the import to reduce the number of fonts, i.e. save the imported file as a picture (PDF) then that might help.
As a foot-note to this, I've seen so-called professionals says Acrobat DC is/was not designed for "complex" editing and multi-user/server use!! In-Design is supposed to be used in those scenarios...
Thanks for the link that explains those fonts. We figured out a work around which is kind of the opposite of what is described above in this string. I found that we can do File-Save As- Optimized PDF and then Unembed every font and we can then read everything.
I'm still not clear why some of our PC's experience this issue and other do not. When an application creates a PDF with embedded fonts, doesn't that imply that all the necessary information required to display those fonts would be embedded in the file? Is there a way that we can install local versions of these CID fonts and then check the "use local fonts" boxes to display them properly?