Solve timestamps (tracked_at / finished_at) are stored without timezone; the app treats them uniformly, which is fine for durations but wrong for local-time semantics.
Blocks: Night Owl achievement. Degrades: Weekend Puzzler precision for non-CET players, ISO-week boundaries of the weekly XP boost for players far from UTC (accepted at launch).
Direction from the launch checklist: likely a Player.timezone column or capture at logging time; country→timezone is ambiguous.
Solve timestamps (tracked_at / finished_at) are stored without timezone; the app treats them uniformly, which is fine for durations but wrong for local-time semantics.
Blocks: Night Owl achievement. Degrades: Weekend Puzzler precision for non-CET players, ISO-week boundaries of the weekly XP boost for players far from UTC (accepted at launch).
Direction from the launch checklist: likely a Player.timezone column or capture at logging time; country→timezone is ambiguous.