I ordered in 2015 a "Gotham Bundle" from https://www.typography.com/fonts/gotham/overview/
It appears there is a compatibility issue between Microsoft Word PC and Microsoft Word for Mac (both being updated to the latest versions available). All operating systems (OS and PC) are updated to the latest available versions too (Windows 10 Professional, 64 bits, macOS Sierra).
The problem doesn't concern each "style" of Gotham, but all the "bold" ones: "Gotham Bold", "Gotham Bold Italic", "Gotham Black", "Gotham Black Italic", "Gotham Ultra" and "Gotham Ultra Italic". I bought other OpenType fonts from other websites (Adobe, for instance), and I am not having this kind of problem (Frutiger is one of them).
If I create a document in Microsoft Word on my PC, the font doesn't appear correctly on My Mac (it looks like "Gotham Book", although it says it is "Gotham Bold"). If I create a document in Microsoft Word on my Mac, the font doesn't appear correctly on my PC either (it is unrecognized, it is named "Gotham" rather than "Gotham Bold"). To help you understand, here are some screenshots...
On a Mac, if you select the style “Gotham Bold”, OpenType version, it will appear correctly:
Although Microsoft Word adds “Bold” to it once style is selected (removing the “Bold”, by clicking on the button, makes the font looks like Gotham Book or Gotham Thin, so since it appears correctly, I leave it as it is):
Now, save the file. Open the same file on a PC. This is what I see on my PC, with the same fonts (OpenType, last version downloaded on the website) installed on it:
Although it says “Gotham”, it doesn’t look like “Gotham Bold”. Actually, it seems the style is unrecognized by the PC, as there is no style called “Gotham” (it’s “Gotham Black”, “Gotham Bold”, “Gotham Book”, and so on, but never “Gotham” alone):
Now, select the sentence, and add “Gotham Bold”, and remove the unnecessary “Bold” by clicking the bold button:
Save the file, and open it again on a Mac. This is what you should see (looks like “Gotham Book”, because we removed the “Bold” on the PC version):
Although it is not exactly “Gotham Bold”, it recognized the font as “Gotham Bold”, without the “bold” that we removed on the PC. If you select “Gotham Bold”:
You should now have what we first created, which is the style “Gotham Bold”, with automatically added “bold” button:
If you save, and open the same file on a PC again, you will get the same problem, again.
This is the problem: compatibility. All the “bolded” versions of “Gotham”, which is “Gotham Bold”, “Gotham Ultra”, and “Gotham Black”, have this issue.
What I already tried:
Contact IT support from the website: they were not able to "reproduce" the issue, although I believe they never understood the problem either (the person didn't try on multiple OS's, only on one, which is not the problem);
I was given the TrueType format of these fonts: they behave even worse than the OpenType;
Uninstalled fonts on both OS's (Mac and PC), rebooted both, reinstalled from the latest versions available on the website, tried again: still the same issue.
I don't know what else can be done. Thanks for your help!