http://monerotoruzizulg5ttgat2emf4d6fbmiea25detrmmy7erypseyteyd.onion/nb-no/2021/09/20/post-mortem-of-decoy-selection-bugs.html
When the paper's recommendation was first implemented in Monero v0.13.0.0 , the wallet correctly applied the observed spending pattern from the tip of the blockchain when selecting decoys. However, when the algorithm was upgraded in v0.14.1.0 , the algorithm applied the observed spending pattern from 10 blocks prior to the chain tip.