Troubleshooting Hub

This hub centralizes common ta4j issues for production-minded users.

Fast triage matrix

Symptom	Likely cause	First place to check
Indicator output does not match external charting tool	Warmup or initialization differences; data-length dependence	FAQ, Technical Indicators
Strategy behaves differently in live vs backtest	Execution assumptions differ (fill timing, partial fills, costs)	Backtesting, Live Trading
Strategy keeps buying (or selling) repeatedly on one candle	Live-candle evaluation without tradingRecord context or fill-sync/de-dup guards	Live Candle vs Closed Candle Evaluation, Live Trading
Unrealized/open-position numbers look wrong	Trade recording mismatch or lot policy misunderstanding	Live Trading, Live Trading Runbook
Results change after enabling moving windows	Historical bars evicted by setMaximumBarCount	Bar Series and Bars
Noisy or unstable leaderboard across reruns	Overfitting, weak validation geometry, or non-deterministic data pipeline	Walk-Forward Research, Backtesting Realism Checklist
Charting fails in CI/headless environment	GUI rendering unavailable	Charting

Deep-dive troubleshooting paths

Data and series issues

• Validate symbol, interval, and timezone alignment
• Check for gaps, duplicated bars, and late bars
• Confirm deterministic reconstruction of the same bar range

Read:

• Data Sources
• Bar Series and Bars

Indicator and strategy issues

• Validate unstable/warmup bars
• Confirm no accidental future-data usage in custom indicators/rules
• Compare component values step by step before testing composed strategy behavior

Read:

• Technical Indicators
• Trading Strategies
• FAQ

Execution and trading-record issues

• Distinguish order intent from confirmed fills
• Decide explicitly between closed-candle and live-candle evaluation
• Use shouldEnter(index, tradingRecord) / shouldExit(index, tradingRecord) in live loops
• Verify ExecutionMatchPolicy behavior for partial exits
• Reconcile local record state with broker/account state after failures

Read:

• Backtesting
• Live Trading
• Live Candle vs Closed Candle Evaluation
• Live Trading Runbook

Evaluation and model-quality issues

• Confirm metric set includes both return and risk
• Audit train/test split and walk-forward design
• Validate strategy ranking logic and weighting assumptions

Read:

• Analysis Criteria and Risk Metrics
• Walk-Forward Research
• Backtesting Realism Checklist

Escalation checklist

Before opening an issue:

1. Capture exact dataset source, symbol, and date range
2. Capture strategy parameters and execution model
3. Include reproducible command and expected vs actual behavior
4. Include logs or chart snapshots that isolate the discrepancy

Escalation flow:

1. Check Execution Decision Matrix for model-assumption mismatch
2. Verify canonical run behavior with Examples Expected Outputs
3. Apply operational recovery steps in Live Trading Runbook
4. Open an issue through Found a Bug?