Align Distribution - Align to Key Object Bugged - Illustrator CC 26.2.1

The problem seems to be the original Artboard size of your file and Adobe's solution to larger Artboards  - to create a 1/100 scale file.

If you create a file with an Artboard larger then that magic number - 226" and then subsequently reduce its size, the Align Distribution will remain at 1/100.   So if you try to align shapes to a key object at .5" apart, the result will be a 5" spaces, even though the tool says .5", resulting in apoplectic hair tearing.