QTemporaryFile: file not being created in Qt 5.11

We have some tests implemented which use QTemporaryFile. We've found that some tests fail when upgrading from Qt 5.9.8 to Qt 5.11.3, if QTemporaryFile#fileName() doesn't get called after calling QTemporaryFile#open(). We use Xubuntu 16.04 for development.

Basically, this is the simplest test case:

TEST(tempFileTest, test1) 
{ 
  QTemporaryFile temp; 
  ASSERT_TRUE(temp.open()); 
  ASSERT_TRUE(temp.exists()); //Fails here 
} 

TEST(tempFileTest, test2) 
{ 
  QTemporaryFile temp; 
  ASSERT_TRUE(temp.open()); 
  temp.fileName(); 
  ASSERT_TRUE(temp.exists()); //Passes 
}