"with(VectorCalculus)", the vectors are displayed in "BasisFormat", which means the components are written as a linear combination of basis vectors. There is a confirmed bug with the display when the first component(s) is(are) zero, and the next component is -1. I’ll just show it:
> < 0,-1,0 >; the result is displayed incorrectly as e[y]. > 2*%;
the result is correctly displayed as (-2)e[y].
Similarly:
> < 0,0,-1 >; e[z] > 2*%; (-2)e[z]
Watch out for it in results, because it could be quite misleading. A way to work around it is to turn off the basis format option:
> BasisFormat(false);
Or (as I’d be more inclined to do) just do a verification on any results of the "possibly-erroneous form " <0,0,..,1,..> by multiplying by "1." before making note of the result.