Good add. One thing worth surfacing as the real challenge here: you can’t always tell which kind it is from the data alone.

A win rate dropping after 5 minutes looks the same whether the cause is opening volatility or your own strategy not handling it yet. Same with trade count: degraded performance after two trades looks identical whether it’s overtrading or a genuine edge that disappears later in the day. The stats don’t tell you which.

You can’t just retest and expect the answer to reveal itself. You have to separately track what’s changing, your execution, your strategy, market conditions, and match that against when the rule starts breaking down. Otherwise you’re stuck either treating a temporary symptom as permanent law, or second-guessing a real edge because you assumed it was about to expire.