My stocks on IBKR have been growing, but my net liquidation value does not tally with the increase growth (unrealised p&l) why is that so?

Are you holding any options positions? Options positions with negative P/L could be affecting your NLV.

Alternatively, if your stocks are in a currency that is different from your bsae currency, the value of your investments might remain the same if the currency which your stocks are denominated in is depreciating against your base currency.

Have you factored in fx losses into your calculations?