Visible crew/equipment: When Sheriff Harry Truman takes the call from Pete Martell at the police station, a reflection of a seated crew member wearing headphones (it actually looks very much like David Lynch!) is visible in the glass divider of the office the Sheriff enters to answer the phone. Clear as day. (00:05:13)
Continuity mistake: When Lucy is badly explaining to Sheriff Harry Truman which phone she transferred the call to, in the window reflection, you can see the Sheriff moving around the office to find the phone. But in the close-up cutaways of Harry, he is standing in one place. (00:05:07)
Continuity mistake: When Pete Martell finds Laura Palmer's body, there is a piece of wood on the ground near Laura's head as he approaches her. It disappears between shots. (00:04:20)
Continuity mistake: The credit has "Lucy Morgan." Later, her name becomes "Moran"; see the nameplate on the desk.
Answer: The answer to pretty much any question beginning with "Has David Lynch ever explained _______?" is: no.