You have a family tabled part that has a patterned feature. The dimensions of the spacing and number of instances of the patterned feature are included in the family table. Then you make a 2d repeat region on a drawing and show the spacing dimension of the pattern. When you change the number of instances in the pattern to 1, the spacing dimension no longer applies because there is no spacing anymore with only 1 feature. So the spacing dimension should change to a dash symbol to indicate that it is no longer present. But it does not do this. Instead, the 2d repeat region will show any dimension that happens to be in the family table for the spacing.
Here is an example of what it looks like. In the row TEST_2, the dimension "B" should show a dash (-) instead of 3.00 to indicate that "B" does not exist in this part.