That's definitely quite unusual. Could you try clearing the app cache to see if this helps? You can do this by heading into Settings > Apps > Samsung Members > Storage > Clear cache. If this doesn't help, please tap on 'Clear data' then restart your phone.
Which benefit are you trying to redeem?
If you're not experiencing issues with other apps on your phone, it's likely the issue is isolated to the app, rather than the phone, so I wouldn't advise performing a factory reset. I'm currently using a S20+ and there doesn't seem to be an issue with the Benefit section. Could you check to see if your phone is running on the latest software by heading into the Settings > Software update > Download and install.
Hmm, okay. Let's try a Soft Reset as it tends to fix a lot of minor bugs. It won't delete any data from your phone, but will reboot it. To do this, hold the Power and Volume Down buttons for around 10 seconds.