Problem with Arial font rendering

Hi Community,

  We have a little problem with Adobe Reader DC and several clients. As you see in first image, the font is weird, yet it's basic Arial Font.
After multiple searches, we found a file with the sweet name : UserCache64.bin into folder appdata\local\adobe\Acrobat\DC and after flush or save this.... magic we have a good font into second image. 

But this solution is not durable. After few days open and close Adobe Reader, this problem is back on client station.

The attached file is not an 8bf extension, for sure, but it's the guilty in this adventure. Can you see for a lasting solution, please.
Best regard.

Léopold.