I’ve run into this issue a couple times when marking up academic papers from my google drive. If there is a minus sign in an inline math equation, I can’t highlight anything after it on the page. The selection jumps from where I make it to begin at the minus sign, and doesn’t highlight anything.
As an example, open up the pdf at the link below. On page 3, there is a minus sign at the top of the right column. Try to highlight any text below that equation.
I cannot seem to replicate your issue, I’ve tried both chrome and firefox with the pdf you have specfied in the question.
Attached is a screenshot of highlighting after the minus sign,
May I ask what browser(s), OS etc… that you are encountering this problem on?
Also can you please provide a screenshot of the specific area that cannot be highlighted?
I’d be happy to fix this problem immediately if I could replicate it.