When I define

<logging>
        <log type="coverage-html" 
             target="./tests/reports/coverage" 
             lowUpperBound="90"
             highLowerBound="50" />
</logging>

in my phpunit.xml, the coverage reporter (or PHPUnit) does not complain that the bounds are conflicting (high starts at 50, but low ends at 90). It allows rendering the HTML report, but the result is a bit off, as in it just disregards the middle bounds (yellow), and only renders red and green charts with some logic.

I think this should be an error or warning of some sort, if the user gives conflicting bounds values?