NSE had a pre-open session at 9am and 11.15am but the markets were stopped due to a feed issue. The markets then finally started at 12.15am. The price of 2843 could’ve been a stray tick traded when the markets started after one of the first two pre-open sessions and then stopped due to a market depth issue.
Also, at the end of the day, there will be a difference between the OHLC value of minute/hourly candles as compared to OHLC value of daily candles. Read this post for more info: