The bug

The category containing the assistants Per Landin and Tom Stone under Mojang is titled Creative Communications Assistant, and needs to be pluralized, as there is more than one assistant with that title.

Here is a part of the credits that demonstrates the bug:

Creative Communications Assistant
   Per Landin
   Tom Stone

Fix

The title should be Creative Communications Assistants to be consistent with other titles that contain more than one person.

Creative Communications Assistants
   Per Landin
   Tom Stone

I am going to attach a resource pack with the fix for this issue.