Reason for straight and sqaure flowlines: Hydrology

[RheannaNeidinger]

Hello,

I have created flowlines using the hydrology toolset in ArcGIS Pro.  Most of the lines look good except for a few are off and do not look like natural flowlines.  I attached pictures as examples.  Why is this happening and does anyone know what it means?

[BenMissimer]

Need to run smoothline tool against it.