It seems that flexbox should fill all available space in width, but for some reason, the row I inspected is not doing so. Even though it's set to display flex and there doesn't seem to be anything unusual about it, Chrome indicates that there is plenty of space to be filled.
Prior to this problematic row, I created another div with just d-flex and a red background, which worked perfectly by filling all available width space. So why is this particular row failing to do the same? That remains the question.
Despite searching the internet high and low for an answer, none could be found.
<div class="container">
<div class="row justify-content-md-center">
<div class="col-10 pb-2 text-justify news_content">
test
</div>
</div>
</div>