It doesn't happen all the time but sometimes I am getting a music overlap. It first started when I was in Coerthas. The Coerthas music/battle theme music would play simultaneously. I logged off and it semi corrected the issue. However later in the day I started the Ifrit quest. After I got to Limsa Lominsa to fight the NMs it started again. Then the LL music and the Gridania music started overlapping.