Bonus share average cost adjustment

One of my stock recently underwent bonus share allotment, because of which share price has reduced numerically to 1/4th of it’s previous value. But my average buy price still shows old as per the prior bonus price. Can anyone clarifies how many days does Zerodha/CDSL takes to adjust average buy price to the new split price?

This should be fixed once Bonus Shares are credited to your Demat account, from record date it can take around 10-15 days for Bonus Shares to get credited.