I could not reproduce these errors for some reason. However, I corrected one mistake on line 409 in subfunction "trvar", where "selectedVariables" is skipped because of a typo. I hope this solves the problem you found.
In addition, I added "selectedVariables" functionality also in subfunction "ginput". It was missing also in Matern-3/2 already before adding the derivatives, so I suspect that this might not have affected on your tests.
I could not reproduce these errors for some reason. However, I corrected one mistake on line 409 in subfunction "trvar", where "selectedVariables" is skipped because of a typo. I hope this solves the problem you found.
In addition, I added "selectedVariables" functionality also in subfunction "ginput". It was missing also in Matern-3/2 already before adding the derivatives, so I suspect that this might not have affected on your tests.