Your buy average on Console is determined using the FIFO (first in, first out) method. However, after corporate actions such as bonus, splits, rights issue, de-merger, merger, and others, your buy average may become inaccurate.
Zerodha manually updates the adjustment for such corporate actions once they are completed and all relevant information is provided by the company/exchanges. This process typically takes around 2 weeks from the date of the corporate action.