Road Elevation Profile incomplete

[MaryEllenStRomain]

Hey y'all - 

I've been working on a slope analysis recently and I keep running into this problem.

For longer segments of trails or roads, the profile that's created shows missing segments.

Process: I interpolated line layer using a DEM and then created a Profile Graph by right clicking the interpolated layer and going to the Create Chart options. See missing segment toward end of trail profile:

This is the second time this has happened to me while doing this. Different DEMs and different line layers. 

Can someone help me with this? 

Thanks!