I recently got a 5v/3.3v power supply #PRT-13032 and noticed that the cluster of headers on each corner of the board are not all aligned on .1" center. the group of 4 that are gnd/vcc on each end are ever so slighty off .1" header spacing. headers will go in on a pcb grid board with a little force but the (+/-) header in the middle near the power connector are way off.
If you all do another run of that board you should align all the headers on a .1" grid with each other.
I have noticed that the dimensions between the power rails and the rest of the tie points on my breadboards seem to vary from brand to brand. The dimensions vary between the power rails on both sides of the breadboard as well.
I believe sparkfun designed these to fit the breadboards they carry although, it’s possible the dimensions of the boards they carry may have changed over time because I doubt they have had the exact same breadboards the whole time they’ve carried them.