Issue Summary

Jira not considering the color code set for the "Primary button - background color" in the Look and Feel configuration.
This is reproducible on Data Center: Yes

Steps to Reproduce

1. Login to the Jira application.
2. Choose Settings > System.
3. Under USER INTERFACE, select Look and feel.
4. Set the color of "Primary button - background color" to #c00c00.
5. Refresh the Jira browser.
6. You will notice that the color of the Create button changed. 
7. Hover the mouse over the Create button > right click > select inspect
8. Navigate to the Dev tools > Styles section. 
9. Filter background-color as shown in the screenshot.
10. Under ".aui-button:link" section you will notice that the background-color set for the button is showing in a different color code, ie: #970900 instead of #c00c00. **
    

Expected Results

Expecting a color similar to the one shown in the screenshot below. 

Actual Results

The color set for the create button is different.

Workaround

Adding the following tag via announcebanner will set the color code to #c00c00 

<style type="text/css">
.aui-button.aui-button-primary {
background: #c00c00;
}
</style>

A side effect noticed with this approach is, that other buttons (eg: Log In) color also changes.

Please note, the issue is not reproducible in the Jira version 9.15.0