A few thoughts

Off the bat, this is unacceptable.  This isn't a specialized instruction flaking out in certain circumstances - this is core syntax / logic that the customer will never question unless given a reason to do so (like just now).  So I agree with the comment above about honesty being required. 

The Optimizer.... I wouldn't be surprised if many users didn't know about the SCL Optimizer - I discovered it by accident when doing speed tests on different instructions.  One thing I will say is that if you are going to do optimization, you have to get it right - it must be as bullet-proof as anything else in your compiler.  This seems to be the way optimization's treated in Visual Studio.  And I also think that the user should be adequately made aware of its existence.

We have just recently started to roll out V19 in all our new equipment, I'm glad I ran into this and see that there is an update already available. 

thanks for this.

Regards.