It's worth noting that so do «wo' DevtaHjaj ghawran» and «wo' ghawran
DevtaHjaj», which are used in KGT to illustrate toast grammar.

As you say, these are exceptions used in toasts, so that doesn't count.

I don't believe the first example is meant to be an exception; according to KGT:
"If uttered as a wish, hope, or aspiration - but not as a toast - the normal word order applies: {wo' DevtaHjaj ghawran} ("May Gowron continue to lead the empire")."

It might still be an error, though.

What you do is count up exceptional circumstances. If a given piece of canon (1) is a toast, which uses special grammar, and (2) violates a clear rule, that's two reasons to be uncertain about the correctness of that canon. The more reasons to doubt the grammar of an utterance, the less certain you can be of the explanation of that sentence.

But we're not talking about Okrandian canon here; we're talking about stuff Qov wrote. Whether it's filmed or not, it has no more authority than Worf belching out ka'blah'blah'cha, until Okrand says Maltz has an opinion on it. Naturally, Okrand would look at anything Qov wrote and say, "Oh, sure, that's because..." and give us an explanation. But until he does that, it's not canonical Klingon.

Personally, I like to use phrases such as {X-ta'jaj X-taHbogh Hoch.} to wish people success. I'm fine with those being {mu'mey ru'}, though.

But if you always do that, they're not really mu'mey ru'. You're taking the exceptions to the language and applying them generally, while telling yourself that you're not really doing that.

It would be kind of like constantly telling people, May you are happy or May you are successful. People would get you the first time they heard it, and figured you just flubbed the sentence in the moment, but if you kept saying that, they'd start to look at you funny. Someone would ask, "Why do you say are instead of be?" Now, violating the Klingon rule gives you a more versatile sentence than violating my English examples, and that's why you'd do it, but the effect on the listener would be similar.

-- 
SuStel
http://trimboli.name