For question 1, the color is added to highlight the menu toggle for accessibility reason, if you want to remove that, add this CSS:
.mobile-menu-control-wrapper .menu-toggle {
background-color: transparent;
}
For question 2, I just tested it and it’s working. Based on your description, it sounds like a cache issue or JavaScript conflict.
Try disabling all your cache settings including plugins and server end cache, then test it again, if the issue is gone, then it’s basically a cache issue, try getting in touch with the cache plugin’s support for how to set the plugin correctly to avoid the issue.
Keep us updated!