You open the project in your Mac and you get a bizarre substitution. Let's assume you have created a title on a PC using Arial. Two fonts with apparently the same names may be seen by your OS as entirely different entities. It's a side effect of the way that fonts are handled on both platforms. It's arguably OS-related if you could regard it as a bug at all, in any case.

Whoever described it as a 'known bug' was really quite innacurate.