Hey there! The patch they have implemented was not to prevent duplicates, but rather make them happen very less frequently. They have made an alternative method by resetting the internal checklist since it would not update. Due to the way Sleeper Nodes were created, it was impossible to remove duplication.

Hey there! Bungie wrote this about the nodes (hope it helps!): [quote] When combining Resonate Stems, it is very unlikely that the resulting Override Frequency will unlock a node in your current area. For example, if you need to unlock a node in Heatsink, you should leave Heatsink before creating an Override Frequency. Destiny 2 has an internal checklist of nodes you have unlocked. This checklist is separate from the count you see in game, and prior to this fix, the checklist would frequently be cleared. Clearing this checklist is the reason duplicates were so common. Going forward, the checklist will never be cleared. Note: If you create an Override Frequency for a node that you have opened in the past, you should open the node again instead of deleting the Override Frequency. This will allow the internal checklist to be updated, and help prevent future duplicates. In different terms, the team has created a form of “bad luck protection” for Sleeper Nodes, but the tracking is starting fresh. Get hunting, and you’ll be unlocking a unique emblem before you know it.[/quote] Good luck out there, my friend!