Loads of bull I thought.
Not anymore.
We had a few bad nights of night terror with Jae. At first we couldn't understand why she was screaming for mummy in the middle of the night when she's just beside her. She'd be crying non-stop for an hour, unable to calm down before she became too tired or too hungry to continue. Some night we had to walk her out of the room and see what exactly she need. Still no clue what she wanted.
Then I recall reading something about night terrors, which is different from nightmares. Most of the symptoms matches, the crying, shouting for mummy when mummy is right in front of her, totally unable to express herself or calm herself down. And the remedy; don't over-tire the kid during the day.
Perhaps there's a change in the sleeping time in school. Now we make sure she get to bed by 10pm everyday.