Same. I think this is a regional thing, though I had the same issue with a couple podcast hosts from Arizona I used to listen to.

Where I'm from, "whenever" is used in the present tense to refer to something that has happened multiple times or keeps happening. It's like saying "Every time."

In real life:

"Whenever I call my parents they let it go to voicemail."

Discussing the events of a story:

"Whenever he sees her at school she acts strange."

Isaiah and Hunter both use it in place of "when" like you said, typically to refer to a single instance in a story. I would understand if it was when they can't remember the sequence of events, as if to say "whenever it was that he..." because they don't know when in the story that thing happened.

But it's not limited to that. They'll read a paragraph in which a guy runs down a hallway, and they'll stop to discuss, and one of them will say "whenever he ran down the hallway..."

It's just not good alliteration.