They said this in the 7.38 patch notes:

(Resolved Issues)
  • An issue wherein the statuses Light Vengeance and Dark Vengeance, which are granted by moving over certain floor sections in the area marked by stone 99 of Pilgrim's Traverse, the Final Verse, and the Final Verse (Quantum), were not granted to players experiencing lag or other network issues.
    * We have implemented measures to reduce the impact of network issues on these duties, and will continue to make improvements in the future.