Why doesn't Euron get angry when Tyrion speaks about Cersei's pregnancy?

Question

In S07E7 Tyrion finds out Cersei is pregnant, Jaime being the father. Tyrion then leaves King's Landing.

In S08E1 Euron wants to sleep with Cersei, but she says that he must wait ("You want a whore, buy one. You want a queen, earn her").

In S08E4 Cersei, having finally slept with Euron, lies to him and says she's expecting a baby from him.

Later in S08E4 Tyrion goes back to King's Landing and tries to convince Cersei to surrender. In doing so, he mentions her pregnancy. Euron is near Cersei so he surely hears that.

Why doesn't Euron get angry? Even if he's not the most clever character, he must realize that if Tyrion knows Cersei is expecting that means she got pregnant before Tyrion left King's Landing, and so before she slept with Euron.

Answer 1

DariM makes an commendable effort. However the canonical answer as given by director David Nutter is:

What did Euron think when Tyrion revealed that he knew about Cersei’s baby?

In the episode, Cersei (Lena Headey) tells Euron (Pilou Asbæk) that he is the father of her unborn baby for the first time we see on-screen. There’s no 23andMe in Westeros, so Captain Jack Sparrow Euron buys it ― having no idea that Jaime (Nikolaj Coster-Waldau) is the child’s actual father.

They’re one big, happy, murderous family for about two minutes until the army of Daenerys (Emilia Clarke) meets with Cersei at the gates of King’s Landing. Tyrion (Peter Dinklage) tries to plead with his sister to surrender, begging her to do it for the life of her child.

But wait.

Since Euron just found out about the baby, and he’s standing right behind Cersei in the scene, wouldn’t he question how Tyrion knew this information? That’s what fans were wondering after the episode.

For Nutter, the scene wasn’t really about that.

“I think Euron, he’s not paying that much attention,” Nutter said, explaining that the scene was more about Tyrion appealing to Cersei’s softer side.

Apparently, Tyrion wanted Cersei to “realize that she wasn’t a monster at all, that she was really, truly a mother.”

“That was an intense scene,” Nutter continued. “I think any type of Euron intrusion there would’ve weakened the intent of what we were trying to tell.”

Source

Answer 2

I can run through a few options here, but I know of no canon source that answers this point, at this point in time.

Euron never realised that Tyrion knew this prior to his own knowledge

Even if he's not the most clever character, he must realize ...

Must he? There's a host of emotions that can run through any person at any given point in time. Euron is pretty arrogant and cruel, he may have been paying more attention to what he saw as the pathetic sight of Tyrion begging for Cersei to hold back. He may have been expecting Cersei to let arrows fly at Tyrion at any point in time. He may have been paying more attention to the dragon, to Missandei in anticipation of her execution.

He may have been paying attention, and still not have realised the implication; after all, plenty of viewers didn't instantly realise it until it was pointed out to them.

Euron may think there is another explanation

While he may be surprised that Tyrion knows, there are other explanations for how Tyrion gained that knowledge. The possibility of spies is ever-present, and Varys is considered to be a competent spymaster.

Euron does not care

So let's say he concludes that Cersei lied to him personally about the baby being his. Cersei is still acting as if the baby is his, he has every expectation that the baby will be publicly acknowledged as his, etc. Is this something he would want to make a fuss about? Pretty much the only thing we're shown him to care about is being in power, overpowering people he has power over, and that he has fucked the queen^*.

If the child is acknowledged as his, and therefore gives him a stronger hold on power as Cersei's consort, does he have a reason to care?

_{*. And later, something about being the guy who killed the Kingslayer.}