whatsapp freezes on iphone 7plus

My WhatsApp freezes every 2nd or 3rd tap on the messages. I tried restarting the app first then the phone but it didn't help. Removed and reinstalled WhatsApp but still the issue occurs every time I have many messages in the group chat. Hard reset of the device also didn't help. Is this the apple issue or WhatsApp? How can I resolve? Any advise will be appreciated. Thanks.