Linked Table in Dataflow returns different results than original table

In the last week I have encountered a mind boggling error with power bi dataflow in both linked table and power bi desktop.  Here is an example table that contains a dimensional table.

Below is a table that refers back to this initial table in a further dataflow that contains no additional steps.

Clearly the linked table is adding a new line for no reason that contains a empty value.  This is causing my Datasets to fail to refresh as this is creating duplicate values in 1 - many joins further down the line.

Have people noticed this happening recently, or am i missing something that changed in my dataflows in the last week.  

This is happening in many of my dataflows where it is adding one additional column with a blank value.