UK banking apps showing customers other users' transactions (opens in new tab)

Recently Lloyds Banking Group has upgraded their apps so that you can see details from all your accounts with them in every app (some functionality still needs the right brands app though).

There's obviously some magic to glue different accounts together without user input, so I can see my Scottish Widows pension and Halifax credit card balances in my Lloyds Bank app[1], even though I have separate logins for each brand's website and app. Possibly my National Insurance number and address I'd guess? But I can see it going badly wrong if they get the magic merging wrong...

[1] Clearly I need to open a Bank of Scotland account to get the full set.

Maybe some session sharing issue? Wouldn't show up if you weren't testing multiple users at the same time.

Yes, hope they publish a post mortem of the cause, will be interesting to see how this could have happened.

Well at least there Opex will be low enough to handle the outflows of customer as they close their accounts.