Potential bug - Hide duplicate Visual Studio squiggles

I finally found the cause of an issue I'd been having for weeks and not finding any viable solutions until now. Looking at the solution and the situation the issue appeared in, makes me wonder if this is not intended.

Issue: Red squiggles on compile errors don't appear. This only occurs in one file in my project. The file in question has over 10k lines. Splitting the class into multiple files with a reduced total line count did fix the issue, but wasn't a viable solution (the project is not mine, I'm just working in it).

Solution: As mentioned here (stack overflow link), unchecking the option “Hide only those Visual Studio squiggles that duplicate ReSharper code analysis highlightings” under “Environment → Editor → Visual Studio Features” fixed the issue.

Given the (very confusingly worded) option name, and the fact that reducing the line count had an effect, I don't think this is intended?

Bug?