Another 4x4 question

[rei]

I'm solving for the last 4 centers and have all vertical 1x2 blocks except on one face i have two colors each diagonal from each other. example:
[R][O]
[O][R]

how do I fix this, this happens a lot and its the only thing thats getting me

 

[Vulosity]

Do r U r'. Adjust the U face, and do r U r'.

Depending on the case, this is just one of them.