As per SEBI regulations, only 80% of the delivery sell amount is made available to invest within 30 minutes after a sell transaction, while the remaining 20% will be added to your Groww balance and made available to invest by the end of the day. 

You will be able to withdraw the whole sell amount after 10 AM on T+1 day i.e. on the next settlement day.

For e.g.,
If you sell a stock from your holdings on Friday, 80% amount will be added to Groww balance immediately, which can be used to invest. The remaining 20% amount will be added on Friday night, which will be available to invest. You can withdraw the 100% delivery sell amount after 10AM on Monday.