I'm using Premiere Pro CS6 (cloud version) on Windows 7.
When rendering my project to H264 I get a glitch on some of my titles. I don't have that problem when rendering to Quicktime with H264 codec.
This is how it looks:
I suppose it's got something to do with transparency? Any ideas?
Try a different player like VLC.
Avoid Quicktime on a PC unless you really need it for something specific.
If you are exporting for Vimeo or YouTube or your own site, use H.264 but not the one in the Quicktime wrapper. Use the H.24 presets and get a mp4 file extension.