In ARR zones there are 4 nodes per group. When you engage a node, it resets the 2nd prior node (the one before the one before you're at), so you can avoid one node per group.

There are 6 nodes per group in HW and SB zones, set up in 3 pair. Engaging a node resets the 2nd prior PAIR. You're hitting pair A, then pair B. You need to engage pair C to reset both nodes in pair A.