By default, the FAQ title font style is bold and has a light shadow just below the text. For some themes, it seems blurry. You can easily remove that shadow and change the font style in to normal.
Go to the FAQ settings page, and bottom of the page, you will get the option to insert custom CSS code. Just add the following lines of code in there and save. Your issue will be solved.
.ac-container label{
font-weight: normal;
text-shadow: none;
}