DST phantom window: 21-day offset risk for exchange schedule logic #557
Description
Flagging a live issue that affects any bot using exchange schedule logic.
US DST shifted March 8. UK/EU doesn't shift until March 29. For the next 13 days, any bot using hardcoded UTC offsets for exchange open/close windows will be off by exactly 1 hour.
For Jesse specifically — if any strategy uses is_market_open() or time-based filters that reference traditional exchange hours (for avoiding low-liquidity windows, scheduling entries around market opens, or cross-referencing spot/futures sessions), the offset is currently wrong for US venues.
Built a demo that shows the exact failure mode: https://github.com/LembaGang/dst-exploit-demo — runs in under 5 seconds, no network calls required.
Worth a check before March 29 when EU clocks change and the window resets.