IOS app - pin and use biometric sign-in EVERY time

Is this a known fault - every time I go to log in to my InvestEngine account on my iPhone app (which is up to date BTW), it asks me for my username and password - no issue with that.

It then asks me to set-up a 4-digit pin - and repeat, which I seem to have to do EVERY time I log in, and then it asks me if I wish to use FaceID - which I do, and it registers this and then I’m in.

But next time, I have to go through this process all over again - is everyone with the iOS app experiencing the same?

just a fingerprint or password with android samsung.

is there a checkbox to remember device for 30 days?

It’s a password or FaceID for iOS too, and a tick-box to “remember me”, but despite selecting this, it seems to want me to create a 4-digit pin, and asks me if I’d like to register FaceID, every single time.

Have removed the app and reinstalled, but to no avail.