The filter Select / Dropdown List value is invisible in a few special cases.

My table configuration includes both: "Enable advanced column Filters" and "Show filters in a form above the table".

When a new select filter dropdown list value is chosen, it is initially invisible. One way to make it become visible is to click on the table.

Also, when I mouse-over the select filter dropdown list it becomes invisible. 

I have included the following CSS in my theme overrides to temporarily fix this issue:

/* bugfix:  Filter values to correctly display after initially being selected */
.wpDataTables .wpDataTableFilterSection .btn.dropdown-toggle.btn-default:hover,
.wpDataTables .wpDataTableFilterSection .btn.dropdown-toggle.btn-default:focus
{
    color: black !important;
}

Thanks!
Corky.

P.S. - I have a couple other issues I am submitting separately for simpler tracking.