Yes. But some posters seem to take that as conclusive evidence that WotC has abandoned any QA ambitions regarding characters that use their official material together.
I could be snarky and say that WotC abandoned any pretense for QA when they announced 5E in the first place**, but I'll satisfy myself by merely clarifying my point:
The idea that 'WotC should philosophically test their material against all other material for balance, therefore they do' is not a statement that reflects reality. As skerrit points out, there are numerous statements by the designers that they simply don't do this, despite your insistence that they must do this because...well, it's not really clear why they must do this except for your insistence that, if they don't, they're somehow not earning the money they're getting from their customers.
That's the puzzling thing -- it's not that the statement is *wrong*, it's that it doesn't reflect reality and thus has no meaningful interaction with any state of existence that's able to be productively discussed.
** - I mean, for crying out loud, they actually released a mass combat system for 5E for playtest and never noticed that, if the two units in contact have combat values that differ by more than the numbers you can roll on a d20, that there was no useful effect from rolling the die. If I wanted to make the argument that most Unearthed Arcana material is written the night before it's supposed to go out on the website, as if it were some high-school game-design class homework, that's where I'd start my argument.
--
Pauper