This is a mistake that can happen even to experienced mechanics. You get distracted for one second and - boom! - you got yourself a gear pump that will work but will not last. I am referring to the position of the lubrication grooves of replaceable journal bearing bushings that you commonly find in larger gear pumps.
Take a good look at what the excessive wear of an incorrectly mounted bushing looks like - the pump it came from lasted for less than a month after the overhaul. So, if you position the groove so that the load is directed against it (and gear pump shafts are notoriously side-loaded) - the bushing will fail.
I suggest consulting the service manual for the correct position of the grooves. For this Commercial pump, for example, the correct position is grooves facing up and down.