This is the kind of thing that can drive a beginner crazy. The behavior of the engine changes as a result of including different libraries. The engine isn't extended, it is changed. This makes for a very tough learning curve.
I accidently tripped across a help entry that illustrated the specific frustration I have been having. Starved for examples I went to the web for material on how to perform certain tasks in Maple. I copy and paste and study the working examples to understand how Maple implements vectors and matrices. I then try to expand on the examples and discovered the technical note on linearalg vs LinearAlgebra. Here is where it is all laid out.
This seemingly small innocuous entry explains why the vectors are different than Vectors. It describes why the departure from lists and arrays as a metaphor for vectors. I understand their logic and even agree with it. The problem is that it including different libraries changes how Maple interprets input. If I create a vector (using the <>1 a2 a3 ... > construct) without any package open I get one result. I include LinearAlgebra package and do the same thing and I get a different construct. If I then include VectorCalculus i get an even different construct.