:TagsGenerate only generates some tags compared to :TagsGenerate!

[still-dreaming-1]

I ran :TagsGenerate!, which created a tags file in the project .git directory. But then when I create new files and save them, the :TagsGenerate command does not generate tags for new php classes. However, if those same classes extend a class already tagged, I can navigate to the class extended from, from inside the new class. This is all attempted just by saving the file, so the tags will be generated automatically. If I manually run :TagsGenerate, I get the same results, the newly created class is not tagged. But If I manually run :TagsGenerate!, it creates tags for the new class. I tried adding a method, and then calling it from another method. When I save, or manually run TagsGenerate, once again, it does not create tags for the method. But if I manually run TagsGenerate!, it does create the tags for the method.