I have soured the internet looking for some information on this topic but couldn’t really find much of anything. I'm not sure if this is something I'm doing or if this is just something PMS was never meant to do it in the first place. The WD TV Live remote has a subtitle and audio button on the top to switch between multiple audio/subtitle options while the video is playing. When I had PSM 1.81 I was able to use these buttons perfectly, but any update after that, including 1.90.1, has somehow disabled these buttons. I reinstalled 1.81 and they work great again.
All the videos I watched that I use these options on all have embedded audio and subs, not srt files. I just wasn't sure if I was missing something or what but any help would be greatly appreciated.