Until an update of Indesign CC2017 up the actually CC2018 version I have sometimes problems with using activated fonts in individual documents.

In these special documents it happens that suddendly Indesign say the font you used before its missing even if it is activated.

It's in the list of fonts, you can choose it, but in this Document you could never use it in anytime again.

The only solution is, to build up a new document and copy all pages or elements in it. This is a realy worse thing to do, especially if you have Dokuments with 150 pages, x Layers and so on.

And no, its not a Problem with a single fonttype (truetyp/Postscript/oft) it happens with all of them. And while you are able to use these fonts in every other Document at the same tim (look screenshot), you are not able to use it in this single bug-documents and never never never again.

I'm really afraid. This f.. bug cost me nerves and a lot of time and for sure money.

I really hope you find and the bug and erase it for ever.