I have a feature class containing several rivers, which are derived from merging individual river segments to make a continuous line. They have been merged using the editor tool. I have calculated the XY start and end coordinates for my merged lines but it is giving me random coordinates of positions which aren't the start and end of the line. Instead, it seems to be giving me start and end XY coordinates of pre-merged segments. How can I alter this so it recognises the line is now a continuous merged line and retrieve the XY start and end coordinates of the merged line not the individual segments. See image attached. The coordinates are calculated as start and end XY using the calculate geometry tool but as you can see, they aren't at the start and end at all.
Were the original pre-merge lines all pointing in a sea to source direction? If not then merging multiple lines flowing in opposite directions will cause the problem you are seeing.
The solution is before you merge, you flip the lines that need flipping so they all flow from a source to sea direction.