After packaging the file and getting the fonts in the "Documents Font" subfolder of your package folder, can you try to install that font?
It will ask me if I want to replace the fonts allready installed. I assume a package action will not change fonts in any way, just copy them to a folder. Right?
I should add some info of my system:
Windows 10, creators update
Adobe CC 2017, all up to date as for august 2017
Workstation, i7 hexacore, 32gb ram, 500gb ssd, 560ti gpu
I used font manager FontXplorer X before, which I unintalled because I thought it was causing the issues. But all remained problematic after that.
That may well violate the font license.
Sure, maybe I'm also working from an illegally squatted building. Not exactly on topic.
And don't worry, I own the license.
It happens to be very much on topic.
Ok sorry then maybe I don't understand the point.
I happen to work often from a packaged folder, from which I own the license and have the fonts already installed on the system. It seems like Indesign is freaking out on the combination of fonts being both installed and in the 'Document fonts' subfolder.
So you think it's not a bug but a violation of the font license?
The purpose of packaging the document fonts is to make sure that everyone involved has the same version of the font. While not a technical requirement, having a license to the font is a legal requirement. Someone else mentioned installing the fonts and that’s why I commented on it.
There should be no reason for you to be using both the installed and document fonts version but InDesign will always look in the document fonts folder first. There are no document fonts bugs that I know of that would cause the kind of conflicts you’re seeing.
Have you considered a font manager?
Yes I understand. But legally all is fine. I happen to be in a legal situation where I work from a package folder. It could think of many reasons to be in this situation, it is not the topic. Iv'e encountered the error on 3 different computers (all Windows 10, Adobe cc 2017), so I wonder if this is a bug in Indesign.
As mentioned I used Linotype FontXplorer X with it's Adobe plugins. I suspected it to be the cause of these issues so I decided to uninstall it earlier this week.