If you take a look at the Fringer talent tree in the bottom row. There are two "Dodge" each connected to the other, and the "end" one is only connected to the first one, so it's not because you can reach it through another part of the tree or something like that.

Is this an error? Or am I missing something? Would the effect of Dodge double if you have them both? Like you spend 2 strain to upgrade defense by 4?.

Read the description of in the the Talents chapter. It's a ranked talent, meaning that you can spend an amount of strain equal to your ranks in Dodge, and the difficulty of that to-hit roll against you are increased by the number of strain spent (it's 1 for 1, not 1 strain for 2 defence).

Okay.. So the 2nd "dodge" is my 2nd rank.. Got it.