The daylight saving week that broke every session filter

[FXS London Scalper]

This creates a multi-week buffer in both spring and autumn where the time delta between New York, London, and your broker's server shifts by a full hour.

The multi-week mismatch is the key point. A London session filter written in New York time shifts by an hour for those weeks. Storing session times in London local time, and converting only at runtime, avoids the problem entirely.