With the new background image for the header component, the search input needs to have an opacity of 1 and new color #f5f6f5.
Tested manually in ACA & ADW- seems ok:
background-color: #F5F6F5 => background-color: rgba(#F5F6F5, 1) => color #F5F6F5 and opacity 1 --> This is valid only if no opacity value is specified for the element which is the case here
[This issue has been reassigned to email@example.com as part of the Alfresco cloud migration project. The reporter of this issue was bmahe]