Next/Previous buttons hidden

[SwiftArtery]

Describe the bug
The next/previous buttons on the toolbar cannot be seen at all, but when tapping where they should be they still work.

To Reproduce
Steps to reproduce the behavior:
Installing the application through Xcode onto my devices shows the next/previous buttons as expected. However, when installing the same build through TestFlight, they do not appear.
These are set up with the superview being of class IQPreviousNextView. No other configuration.

The fields are laid out as so:

Superview (class IQPreviousNextView)
  Scroll View
    UIStackView ("Content Stack")
      UIStackView ("Input Stack")
        UIStackView ("Diameter Stack")
          UILabel
          UITextField
        UIStackView ("Perimeter Stack")
          UILabel
          UITextField
        UIStackView ("Area Stack")
          UILabel
          UITextField

Expected behavior
Buttons should be shown.

Screenshots

Versions

Xcode: 10.0
Mac OS: 10.14
Simulator/Device: iPhone X (iOS 12.0.1), iPhone 6S (iOS 11.3.1)
Library Version: 6.2.0

Additional context
As stated, this works fine when installing the application through Xcode, but not when installing via TestFlight. I have 2 other apps and it works fine for these, where I don't use any UIScrollViews - only multiple nested UIStackViews. Therefore is it possible that it's the UIScrollView causing issues?

[SwiftArtery]

Fixed by running pod deintegrate and then pod install. Not sure what the issue was - I'm guessing a corrupt installation...