I recently came across the following passage, which starts like this:
As my sister began telling me about the scorpion in her bed that stung her as she slumbered, I could feel my eyes popping out of my head.
But, I think that it should have been:
As my sister began telling me about the scorpion that had stung her as she had slumbered, I could feel my eyes popping out of my head.
Context: it's happening in the past, and one of the two characters is telling a story that happened earlier that day.
That’s why I thought the story part of the passage should have been in past perfect- but for some reason, it’s in the past tense.
What could be the reason for that?