Inconsistent text in bibliography X5 Mac

I am using x5 on a Mac, when my citations are formatted into the bibliography, some references are in bold, and in a mixture of Helvetica or Times New Roman font. I can correct these inconsistencies one by one in Word, but with a very long list of references this would be a very slow solution. On a PC I can export the references as a RIS file and then bring them back into ENdnote and this solves the problem, but this does not solve the problem on a Mac. This is also by many other users at my institute. Has anyone else had this problem/found a solution?