Or can it be, out of the blue, the mixed configs, are causing this, when they weren't before.
All cables test out fine.
As long as BOTH ENDS of a cable are wired the same (either A or B) there will be no problem. The signal doesn't care what color the pairs are since the difference between the two schemes just swaps the orange and green pairs. You would have a problem when one end is A and the other B. But since you say the cables test fine then that is not an issue.
As Sam says it's important to know and maintain the standard used in a facility. The only problem mixing both standards will cause is the difficulties techs will have trying to figure out what was used where when it comes time to change things.
-Hal
