We can snap with V on dimension lines. I don't know why, but why not.
BUT : if there is an offset in the settings of the dimension, V will not snap on the vertex of the dimension but on the visible line! I allways see that in TC, if I remember. If it wasn't fixed, it means it's not a bug. Maybe some use it.
For me it's only a lot of mystakes : the dimensions are not the good dimensions since they don't snap on the good vertex. So it's impossible to use "offset", or maybe only at the end of the drawing.
My wish is to have a setting to not snap on this offset, or on dimension lines.