I apologize for not being clear the first time. When I upload a video to my wordpress site, I encoded the video in 720p, and 360p. I do not replace the original 1080p video.
When I watch the video on my site, the 720p and 360p versions of the video are only outputting sound on the right side of my speakers (the balance is 100% on the rightside), but the original 1080p version is balenced correctly with sound on both the left and right.
To answer your question yes, the sound is being changed to mono, whereas the original video is uploaded in stero. This has happened with all the videos I have tried so far.