It just occurred to me that the last show of the 3rd season, Beaver’s Team, Hugh had already gone back north so they had to dub him. Also in the last episode in Season 4, Substitute Father, Ward is just in the beginning and never again. He must have gone back home at the end of the season.

Besides the parts of Beaver's Poster that I've pointed out before that Mathers' dialog is dubbed, I think there are a few other episodes around that one where he dubbed in later, too. (At least he did his own dubbing, unlike Beaumont.) Maybe Mathers had laryngitis.

With Beaumont, they could have done what My Three Sons did with MacMurray--film scenes out of episode order. I've read that's very difficult for the actors, and I can believe it.

You mean MacMurray might have filmed the last scene of an episode first or scenes from different episodes? Like if Hugh had to film a scene from Beaver's Baby Buggy and then a scene from Junior Fire Chief. (I don't know many episodes of My Three Sons)

I noticed many times Mathers had a cold. He often sounded all stuffed up like when he asks June if she ever did dumb stuff. I think that was when he said Ward was a hero in the war. Also I don't recall Beaver's voice cracking like Ernie Douglas.

Re: Mac Murray - yes, I've read they filmed different scenes from different episodes, all out of order, due to his odd contract. They would film parts of his scenes with stand-ins, and go back later and get his parts, probably making it necessary for actors to retake parts of scenes. It must have been really difficult to deal with.

Yes, around the ninth season Barry Livingston's voice was really cracking.

Now that you mention it re Mathers, he did sound stopped up at times. Maybe he had a cold, or maybe he had to have his tonsils out in real life.

It just occurred to me that the last show of the 3rd season, Beaver’s Team, Hugh had already gone back north so they had to dub him. Also in the last episode in Season 4, Substitute Father, Ward is just in the beginning and never again. He must have gone back home at the end of the season.

I believe Barbara Billingsley gave an interview where she said Hugh's mother-in-law died in a car crash at some point during the series and he was never the same after it happened. I think he was supposed to be driving but decided to fly instead. She said he lost interest in the show afterwards. No idea if that is why he left early before the season finale.

^^^^
Well, he did a great job then, not having much interest in the show.

I believe that incident with his mother in law dying in a car crash had occurred very early in the show. I could be wrong but I thought it had to do with Captain Jack and the censors. Hugh had to fly back quickly to do Beaver Gets ‘Spelled and his son drove the car himself and his grandmother was killed. I could be all wrong.

According to Wikipedia his mother-in-law died right before season 3.

https://en.wikipedia.org/wiki/Hugh_Beaumont

In 1959, just before Beaumont began filming the third season of Leave It to Beaver, he flew from his home in Minnesota to Hollywood while his wife, son, and mother-in-law traveled to California by car. An accident on the road killed his mother-in-law and severely injured his son. Jerry Mathers later stated that the tragedy seriously affected Beaumont's participation in the production at the time, with Beaumont often just "walking" through his part.

Wow that is awful stuff to have to live with. Wonder who was driving?

When it comes to walking thru the part, Mathers doesn't have a lot of room to talk, when you consider the later seasons.

The viewer would never know Beaumont was walking thru the part. The only hint of any problem would be that on-location dialog dubbed by another actor in the closing episode of season 3.

I think Hugh had already returned home after they wrapped up season 3 and realized his lines were affected.

I just read the wikipedia bio of Hugh and I never knew he was the narrator of Racket Squad.
If I catch Racket Squad again, I will have to listen.

Hugh had an announcer voice, very easy on the ears.