There is a design in Photoshop or Sketch, for example the layout for 20 pages.
Open the design and see that all goes, because the fonts are not installed in the system.
Set the fonts, everything is OK.
But the layout also need to connect the fonts and sometimes it happens that you incorrectly wrote the path incorrectly wrote something and the font on the page does not connect. To permanently remove fonts from the system and restore to test, too, so me + @ test you might not notice that the font is not connected.
How do you solve this problem?