Could this be a Wonderlic typo?

by Marie
(Arizona)

Undeterminable
Indeterminable

The author of this page uses the word "Undeterminable" for the response to the answer of number 1 (Answers for Spatial Reasoning Sample Wonderlic Test)

While "Indeterminable" is used for the response to the answer of number 5 in the same category.

So do these words mean the same thing, slightly different meaning with a slightly different spelling, or is this a typo?

If this is a typo, should employers and schools trust the creators of the Wonderlic exam for accuracy? Should a persons intelligence be measured by an exam where the creators fail to spell check or proof read for accuracy?

This is a curiosity.

Food for thought.