Why does Tradejini ask to redo KYC while opening an account, even though it was done while opening the bank account?

Banks and brokers follow two different KYC processes. The broking firm must follow the KYC registration process via KRA (KYC Registration Authority), but the bank must follow the KYC registration process via CKYC Agency (Central KYC).

NOTE:

KYC is identified with the PAN number. However, CKYC is identified by a 14-digit number (CKYC number)
KRA is limited to SEBI intermediaries, whereas CKYC is universal for the Banking, financial services and insurance (BFSI) sectors.

As brokers coming within the realm of SEBI and financial institutions, we need to verify and update the latest KYC details with both – the KRA and the CKYC agencies. The KYC is created/ fetched with us during the online EKYC process, and you need not follow any separate process.