Second level drop-down menu becomes transparent after clicking

[brttd]

ProccessWire Version: 3.0.256

When using the new Konkat admin theme, clicking inside of a second-level drop-down menu (for example, clicking just under the divider line which shows underneath the Add New option inside Setup > Templates) makes that whole second-level menu become transparent. If you move your mouse back over the initial drop-down menu, all other second-level menus will also then display as transparent.

Note: this can only happen if you mis-click in the menu. Clicking any of the actual links inside the drop-down menus does not appear to cause the same issue (before navigation occurs). It only happens when mis-clicking on a non-linked area of the menu IE whitespace at top/bottom.