Im following saboteur trapper build and the 3.20 guide tree and the actual tree are different. Actual tree has an extra node??

Normal?

You are comparing two different skill tree versions.
The one in the guide might not be updated.

most guides were made with 3.19 skill tree as GGG did not release 3.20 skill tree before the league, so POB never updated the tree in time for adjustments.
that and many guides are just lazy piles of shit and not to be followed to the letter anyway