disabling "Insert opening or closing brackets" options causes QtCreator crash when typing-in some code

with "Insert opening or closing brackets"  option disabled (unchecked),

when I type "operator int("

in the following code, QtCreator crashes immediately (as soon as the opening parenthesis is typed. It only occurs while in the process of typing from the keyboard, and not when pasting from clipboard etc):

struct X
{
    operator int(); // it doesn't matter what the type is - it could be a QString or whatever
}; 

with "Insert opening or closing brackets"  option enabled (checked),

everything works fine.