Geodesic option on points yields incorrect buffers

[RandyMcGregor_BMcD]

Just about sent a map set out, then realized the buffer distances seemed way off (pink, below). I had entered the distances correctly and the coordinate system of the input points was in the coordinates  I had assumed. I reran, changing nothing except using 'Planar' and it was correct (blue, below). Geodesic is the default. Is this a bug? is there something that causes this to happen that I should know about? 

Thank you,

Randy McGregor

[Dale_Honeycutt]

The geodesic option is correct.  Your map projection (spatial reference) is distorting distances.  See these articles:

https://pro.arcgis.com/en/pro-app/latest/tool-reference/analysis/how-buffer-analysis-works.htm

https://pro.arcgis.com/en/pro-app/3.1/tool-reference/spatial-analyst/geodesic-versus-planar-distance...

Also, do a web search on "Geodesic vs Planar buffers ArcGIS".  You'll find several articles and videos about this.