1. The breakout candle doesn't have higher volume - although the candle day after breakout has higher volume
2. Today's candle seems to be a spinning top - indecision
3. Considering the rally from 902.65 (hammer on 05 April) to top 999.70 (18 April), 951.18 forms the 50% fibonacci retracement level - which was breached on 19th April on closing basis and two more lower closing, it crossed 23.6% retracement level (976.80).
Considering lesser volume, indecision candle and fibonacci level - this may not really be a flag breakout and uptrend could be possible.