Editing a Pattern in a Sketch

Hi,

Does anyone know why when I edit a pattern in sketch mode

to just add more instances of the pattern, it loses the spacing dimension

in the same sketch and I get all kinds of errors?

I have a weldment grating that has vertical and horizontal bars.  If I add more vertical bars by editing the sketch pattern

what I described above happens.  I don't understand the failures.

SolidworksParts And Features