referenced alignments stations shift

I am having issues with extending geometry. I have ramps for an interchange tied to a mainline baseline. When I extend the mainline baseline the ties to the ramps shift the stations do not hold at the original station they shift basically the distance the baseline was extended. I it appears like the tie is set based on the distance from the original beginning of baseline and set to the beginning of the revised baseline. Has any one else experienced this and is there a solution.