What would cause a pushrod to be bent?

took the 45 diesel's hood off today and fixed some guages and then thought I would check the valves as it hasn't been done in a year or two, since I did it once the motor got up and running again.  As I was working through the valves, the intake valve push rod on #6 spun kind of goofy when the valve was all the way closed.  Took off the whole rocker arm assembly to pull the one push rod out and it was bent.   All the others were fine, and the valve lashes were all really close to where they should be, including the one that had the bent push rod.   So what could have caused it to be bent?   The only thing I thought of was if when the rocker arm assembly was previously installed by the guy who rebuilt the motor, it got pinched to one side of the pin and not centered under the adjustment pin and when it got torqued down, it got tweeked, and was figured out when the valves were set but not straightened.  I straightened it out and put it back together and reset everything, and it runs as good as it did before, but it did make me worry a bit, especially consider how much money was put into this thing to get it up and going again. 

Haha thats kinda weird cause when I puled the head off my CA two pushrods were bent.  The reason i pulled the head off in the first place was to re-ring the motor because it was burning oil.  I think my Dad floated a valve or something on it.

I have herd valves run loose will bend pushrods, dont know for  positive