Zappos app for iOS: Light Mode: Text at the top of the screen disappears when logging in or signing up - Why?

iOS 13.1.3
Zappos app for iOS (version 5.7.0)
Date: 10/23/2019

Description:

Minor bug with the Zappos app for iOS.

When the Zappos app is NOT in dark mode, the text (carrier, time, battery icon and percentage) at the top of the screen will disappear whenever the user selects a sign-in or log-in option.

I am pretty sure that I have seen this behavior with other apps on rare occasions. I was surprised to see it here - not sure if this is intended behavior. It does does NOT reproduce with the app set to the new dark more.

Please see the attached screenshots for more information.

Steps to Reproduce:

1. Download the Zappos app for iOS (version 5.7.0)
2. Select "Cart"
3. Select "Sign in to View Them"

Result: The text at the top of the screen (carrier information, time, battery icon and percentage) disappears after the user selects "Sign in to View"

Expected: That iOS UI text should never disappear

Launch the app - select the "Cart" option...

Select "Sign in to view them"...

Text that was at the top of the screen has disappeared!

But it does appear with dark mode? Is it every allowable to have this text disappear?