Bug: Multiple monitoring loops detect ghost simultaneously
- Loop 1: has(tradeId) → true → proceeds
- Loop 2: has(tradeId) → true → ALSO proceeds (race condition)
- Both send Telegram notifications with compounding P&L
Real incident (Dec 2, 2025):
- Manual SHORT at $138.84
- 23 duplicate notifications
- P&L compounded: -$47.96 → -$1,129.24 (23× accumulation)
- Database shows single trade with final compounded value
Fix: Map.delete() returns true if key existed, false if already removed
- Call delete() FIRST
- Check return value
proceeds
- All other loops get false → skip immediately
- Atomic operation prevents race condition
Pattern: This is variant of Common Pitfalls #48, #49, #59, #60, #61
- All had "check then delete" pattern
- All vulnerable to async timing issues
- Solution: "delete then check" pattern
- Map.delete() is synchronous and atomic
Files changed:
- lib/trading/position-manager.ts lines 390-410
Related: DUPLICATE PREVENTED message was working but too late
93dd950821