Parentheses in section titles interfere with on-screen font choice

[Richard Stanton]

When using org mode (9.3.6), I’ve noticed that putting parentheses into a 
section title seems to change the font used to display the title on the screen. 
So, for example, on my machine

* Heading

displays in a red font.

If I add something in parentheses, e.g.,

* Heading (with parentheses)

the title now displays in grey. As I’m typing, the font change occurs the 
moment I type the first character after the open parenthesis.

The behavior is similar for lower level headers too. Is this deliberate? And if 
so, is there a way to put parentheses into section titles without interfering 
with the display font? 

Thanks.

Richard Stanton