This was question I got via email. I'll give the email he sent and then my answer, and then the relevant section from my book Verbal Poker Tells.

Reader email
Hi Zach. I had an interesting hand where a pretty reliable tell didn’t hold up. Here’s the hand history:

4 limps to hero,
Hero makes it 25 on BU with KcQd, Utg (300) and HJ (500) call.

3 WAYS

75 Flop Qc45r
Checks to me, I bet 25, both call

150 Turn 7c
Checks to me, I bet 75, both call.

300 Tc
Utg leads all-in for 130 more, HJ folds.

Hero talks to Utg who seems calm and says, “I don’t have the nut flush,” when hero asks if he has a flush. He slightly emphasized the word “nut.” Anyway I fold and he showed Ah3h which I thought was a bit anomalous. Wondering if you had any thought or could shed any light.

My response

Did you read Verbal Poker Tells? This would fall under a caveat I included about bluffers removing the absolute nuts in order to communicate strength. Because it's fairly obvious to most players who've played a bit that weak-hand statements will mean strength, some players are capable of making a weak-hand statement to communicate that they are strong, and in these cases they'll use the absolute nuts.

So basically, while the pattern will still basically hold even for removal of the nuts, it'll be a bit less likely to apply when players verbally remove the nuts. This is why I recommend, if you want to try to verbally induce responses, to ask about less-nutted strong hands. For instance, here, it would have been better IMO to ask if he had the straight (also because someone with the flush is more willing to deny the straight than they would deny the flush).

It's also kind of interesting that he emphasized the word 'nut', because it makes his statement more superficially obvious; it makes it more likely he's trying to communicate "I have a flush but I don't have the NUT flush." (So in a way, his statement here could be viewed as more of a strong-hand statement and less of a weak-hand statement.) With a lot of the more obvious behavior where a player seems actively drawing attention to something, it's going to be more likely they're using it in a reverse way. In other words; the more subtle (less on-display) the behavior is, the more you can rely on it adhering to the general pattern.

Section from my book Verbal Poker Tells
An exception for bluffers

The main exception to the weak-hand-from-a-bettor-means-strong-hand rule is that a bluffer may occasionally make a statement that eliminates a very strong hand in an attempt to better sell a bluff. This can be considered a case of representing strength by expressing slight weakness.

For example, a player bluffs the river on a board of A♣ 9♠ 8♦ A♥ Q♣. As his opponent considers, the bluffer says: “I don’t have quads; I swear.” By eliminating a powerful hand from his range, he’s attempting to imitate a player who’s trying to talk an opponent into calling. But the bluffer will usually only eliminate a single, very powerful hand; the bluffer doesn’t want to eliminate more than one or two possible value hands even when attempting this deception.

These types of statements can be seen as subtle strong-hand statements. They are basically implying, “While I don’t have this very strong hand, I do have something strong.” (The pattern is discussed more in the chapter Expressing Strength With Slight Weakness.)

Most extreme example I ever saw of this was long enough ago that I've forgotten most details of the hand itself, but here's the gist: 2 players sitting next to each other become involved in a pot. These two didn't know each other before sitting down, but quickly looked to be best of friends as session proceeds. So as this hand gets to the river, a 3rd king hits (K-x-Q-K-K). Player 1 bets and Player 2 jams way over pot. #1 laughs and says 'I'm pretty sure we have the same hand, I've got a queen', and #2 says 'yeah, you're right'. Still in good spirits, #1 says 'You really don't have a king?', and #2 says 'I *SWEAR* to you I don't have a king'. Took a little more time than this, but after his new friend swore he didn't have quads, #1 makes the call, and is shown quads.

While #2 is dragging in chips, #1 says 'I trusted you'. #2 says, half derisively, half to punctuate a lesson, '*NEVER* trust a poker player!'

Not so much banter between them after that.