Reader DC Classic: "Cannot extract embedded font..."

Hi all,

since updating to v2017.011.30099 one of our customers keeps running into the above error message with different files on several computers.

Here's a screenshot:

I can not say wether Helvetica is correctly embedded or not but it looks like it... here are some screenshots of the file properites/fonts tab:

I've already changed to v2015 and to v2018 (continuous track) but the error reappears every time I open this file. Looking through old threads I found several posts about new versions so it seems Adobe needs to release an update. Can someone please give me some advice on this?

Best regards from Solingen,

Sebastian