It is due to specifications that when a QR code displayed on PC is scanned, there is no redirect on PayPay App but redirect is conducted only on PC.
Refer to the following information too:
PayPay for Developers Q&A
It is due to specifications that when a QR code displayed on PC is scanned, there is no redirect on PayPay App but redirect is conducted only on PC.
Refer to the following information too: