I found this site through searching for help on this and found a similar thread on Starling Bank.
I have a OnePlus 7 and had the Santander app happily working on my rooted (with Magisk) phone. Until one day in June they updated the app without me noticing and it now detects root, despite me trying all my old tricks. I saw several complaints that the app even ‘found’ root on non-rooted phones! There has been a further update which may have cured those false positives, but I still can’t hide root. I’ve deleted various apps that I thought may have contributed (including Titanium). They only one I have left to try is Magisk. Any ideas?
OK, now removed Magisk and Magisk manager and still no joy.