Working with the aXe chrome browser extension I noticed some inconsistent behavior. It is only present when we are applying font-weight: bold to a <b> or <span> inside any parent node. When the node is on one line presentationally within the DOM, no color contrast flag, but when its container forces a line break it flags it as unable to determine color contrast.

<p class="content">
   Lorem Ipsum <b>Bold Text</b> and a <b>lot more bold text</b>
</p>

Attached are pictures of the false positives.

offending markup

associated false positive