On Mac, when text in the PDF reader is annotated with a highlighter color, that text cannot be "selected" using the mouse. This prevents selecting and copying the text to paste into, say, a note. The workaround is to delete the highlight annotation, select and copy the text, and then re-annotate the text with the highlighter tool.

The preferred behavior would be to allow clicking and dragging over highlighted text to "select" the text the same as if there was no annotation there.