Svetlana, as a background for the note: the platform tests are run by user after he deployed OpenStack with Fuel. I.e. user deploys OpenStack, then pushes 'Run Platform Tests' button and Fuel ensures that Savanna/Murano/Heat are operating correctly. So the phrase "The Heat, Savanna, and Murano services 
has been tested" does not work here: it is not us who run the tests, it is the user.

As for the phrase "However, the tests may fail due to a bug": the bug makes the tests _completely_ broken, they simply never pass. On the other side, I don't know how to put it better. So if you think it would be better to put it your way, I'll do it.