I ship Codenames AI, a web game. Each game mode keeps its own save in localStorage. Reload the tab, switch to a different mode, come back later: the board, turn, clue history, and in-progress results all come back. That felt like a win until I added spymaster clue targeting.
While drafting a clue, I can click cards on my team. Those clicks sync the clue count and show which words I had in mind. They are visual intent only. They are not part of the clue submission payload.
I assumed that if I reloaded the same game, the UI could restore those highlights too. Same session, same cards, same mental model. On a single-mode refresh that was mostly harmless.
Switching game modes was not. Each mode loads its own 25-card board. Leftover targeting clicks stayed in memory. If a word on the new board matched a card I had highlighted in the previous mode, that new card lit up. I had never clicked it. The board was truthful. The UI was lying about what I was drafting.
Clearing those highlights when the board changed would have stopped the lie. That cheaper fix was not enough. I had already assumed a same-game reload should bring the clicks back. Keeping that assumption and stopping the leak meant persisting the clicks per mode, the same way we persist the board. That would have treated a thinking aid like a move. The collision forced the real question: should coming back restore those clicks at all?
