Lichess puzzle ratings are completely puzzling. For example this

Puzzle issues resulting in a huge drop of puzzle quality (on the 2500+ range) • page 1/1 • Lichess Feedback •

Quantity over quality (ChessTech News)

How good can you get at chess by just completing puzzles, (specifically the training on Lichess app)? - Quora

Getting the same training puzzles repeatedly, no score updates · Issue #813 · lichess-org/lichobile · GitHub

Quantity over quality (ChessTech News)

Chess Sudoku - White to move, Mate in 2 moves — Rätselportal — Logic Masters Deutschland

lichess • Free Online Chess - Apps on Google Play

File:Lichess puzzles updated.png - Wikimedia Commons

Lichess - Wikipedia

Getting the same training puzzles repeatedly, no score updates · Issue #813 · lichess-org/lichobile · GitHub

The vision of Lichess and its founder Thibault Duplessis - ChessBase India

CheckRaiseMate's Blog • Ratings Are Broken •

How to Solve Any Chess Tactics Puzzle