[iOS] App crashes when scrolling up on Monzo chat history

Issue: Monzo chat crashes when I try to scroll up after clicking “Chat History”. This only happens when the blue loading bar is moving across the top of the screen.

NB: I can’t seem to recreate the crash consistently, but I have managed to recreate it a few times using the steps below.

Details to reproduce: Go to Help tab ==> scroll down and click “Chat with us” ==> click “Chat history” ==> immediately scroll up as far as you can.

OS: iOS 12.1.2

Device: iPhone 6

App Version: 2.28.0