'Get Path Length' node bugged or just very inaccurate?

When using the Get Path Length node to get distances on the NavMesh, I get some VERY inconsistent results.
Check the attached pictures, I made a debug tool that measures the absolute distance and the nav distance using the Get Path Length node.
The results are all over the place, can someone clarify? I thought I was going crazy when my AI started moving to locations that I thought had filtered out by using this node…