@sujith - In 1Min historical Nifty Future data, while Price and Volume are changing every min, but OI is changing in every 3Min. This observation is consistent across all expiry of Nifty Future.
I'm using Java SDK.
com.zerodhatech.kiteconnect public HistoricalData getHistoricalData
What is the javakiteconnect version you are using?
Source: Sensibull