Thanks for the question. Here’s how I’d go about making a vector tile group. I used the fract function depicted in the tutorial, which in turn depends on sign. In your vector tile group, did you multiply the x, y and z components of the vector by the number of tiles before supplying the product to fract?
For uniform tiling, a single number is fine; for nonuniform tiling, as above, I used a vector. Below, the group node is applied with a tiling of (5, 3, 0).
Depending on what other nodes you’re working with, in some cases it can be easier to tile the output Fac of a node than the input vector.
As of Blender 2.8, you don’t have to define fract yourself; it is included in the math node.
Hope that helps! Best.