Authorising payments with Tesco Bank app on iPhone used to be seamless.
Make a purchase online - see the pop up on the phone - touch to open - touch to authorise - job done.
Since the summer though there is an embarrassing wait after touch to open whilst the app thinks about opening. Once the wait was so long I bought the same item twice thinking the transaction had not gone through and then had the authorisation codes mismatched to the purchases!

What is going on?
Today Tesco told me that the app was being updated and I hope it is and that that resolves an issue which I have seen for over a month.

Has anyone found a work around for this?

After waiting a minute today (at home with strong wifi and 4G) I pressed the home button to leave the blue loading screen and then went straight back to it and it opened to the authorisation screen immediately.

It has always been odd that touching to authenticate on my iphone SE (still have a home button) first approved the purchase and then started to open the Tesco Bank app from the one touch. I wonder if this is the root of the issue...