Bosch Season 6

Between 12:30 and 12:40 into Episode 10, Detective Vega walks thru the camera shot. Someone approaches from the right and says "Hey there" just before he steps into view.

Vega replies, "Hey Mike."

I'm thinkin Mike is Michael Connolly, author of the Bosch novels. Check the four-minute "Episode 0" at Amazon Prime, "Page to Screen: The Overlook". About 38 seconds in, Michael Connelly talks about S6E1. That could be him.

That's him.

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From the transcript at tvshowtranscripts:

Hey, there.
Hey, Michael.
What up?