Error 538179 occurred at Network Master.ilclass:Shutdown Master.vi

[RTSLVU]

Help! I had to modify a working program to add some logging capability. I did a quick scale down of the existing code to test and now I get this error: 

Error 538179 occurred at Network Master.ilclass:Shutdown Master.vi

This is what this section used to look like: 

all I really did was remove the inner For Loop as we are only concerned about one measurement for this test., and we want it to update as fast as it can.

I attached an even further scaled down version my code that still gets the error.

What am I doing wrong? 

[RTSLVU]

For some reason the scaled down VI I uploaded just started working.

I don't understand why as I did nothing with any of the Modbuss VI's.

It literally started working right before my eyes as I was debugging it!

I had the trace on and was watching the errors that were being thrown by  my "Get Primary Measurement" vi. 

It threw the error 12 times as it tried to get a measurement from each of the 12 meters.

On the next iteration of the while loop, it threw NO ERRORS AND HAS NOT THROWN AN ERROR EVER SINCE!????

But my original program that uses identical code still throw the errors! 

What is going on here?