Your bank unblocks the funds after the allotment of shares. However, certain banks will unblock the funds only after the mandate end date. You can check the mandate end date by visiting kite.zerodha.com/bids/ipo and clicking on the IPO.
Example scenario
The allotment date for GOYALSALT is 5th October. Banks unblock the funds on the refund initiation date, which is the 6th of October. If your bank has not unblocked the funds, it will be done after the mandate end date, i.e. 14th October 2023.
You should request your bank to release the funds if you were not allotted shares anytime after the allotment date. As your funds are only blocked and still remain in your bank account, interest will accrue as usual.