Recurring payment failed

Hello,
Recurring payments failed for variable subscription product. Following might help:
Apr-2019 22:54:45 UTC] IPN request is valid according to PayPal.
[01-Apr-2019 22:54:45 UTC] Found order #1878
[01-Apr-2019 22:54:45 UTC] Payment status: completed
[01-Apr-2019 22:54:45 UTC] Aborting, Invalid type:merch_pmt

I found this on paypal:
merch_pmt : Monthly subscription paid for Website Payments Pro, Reference transactions, or Billing Agreements
https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNandPDTVariables/
That made me thinking why validate_transaction_type function does not have “merch_pmt”

protected function validate_transaction_type( $txn_type ) {
$accepted_types = array( ‘cart’, ‘instant’, ‘express_checkout’, ‘web_accept’, ‘masspay’, ‘send_money’ );
if ( ! in_array( strtolower( $txn_type ), $accepted_types ) ) {
wc_gateway_ppec_log( ‘Aborting, Invalid type:’ . $txn_type );
exit;
}
}

Any help will be highly appreciated.

Regards

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