ArcGIS automatically converting Z units when no Vertical CRS is defined

I have seen this on several tools, but it was most obvious to me when using calculate geometry in the attribute table.

I have a point dataset that has Z values, but no VCS defined. I then used calculate geometry to add those values to the attribute table. In one sample point the calculate geometry in the attribute table was -4.279431. When I pull the z value directly from the SHAPE geometry, I get -14.04009. So it is obvious it is applying a feet to meters conversion. I know Esri has been integrating VCS into the software for a few versions and I realize if I define my VCS I shouldn’t have this problem (confirmed, I don’t).

My question is, why the feet to meters conversion? Can this be defined or turned off somewhere?

ArcGIS 10.7.1