If Jeff and Bogg, or any Voyagers, for that matter, fail to correct history on a mission, what's to stop them from traveling back again and taking another crack at it? Sort of makes the entire premise moot, when you think about it.

The Omni doesn't always show the right coordinates on its map. This happens in multiple episodes.

Throughout the series, the Voyagers often wear the wrong clothes during a time jump. And no matter where they leave their own clothes, they always manage to go back for them in time for the next episode.

Everybody speaks English; perhaps the Omni contains a universal translator.

Created Equal

Billy and Bully

"How'd you rope us like that?" Jeffrey asks Billy the Kid. Trouble is, he didn't; Billy only threw the rope close to the Voyagers so they could grab on.

Fortunately, Billy has extra clothes to lend to the Voyagers. But why's he carrying kid-sized clothes?

When Bogg mounts the running horse, he has the cigar in his mouth--the cigar he just threw away.

Agents of Satan

Abiah raises her skirts a little too high while climbing the rocks, exposing undergarments that don't look very much at home in the 17th century.

Worlds Apart

Jeffrey comments on mastodons found frozen in Siberia. They were actually mammoths, not mastodons.

Cleo and the Babe

The Day the Rebs Took Lincoln

Marian's lips don't move when she invites Bogg to come back any time.

If Bogg was planning to disarm Jane Phillips, he should've done it while Lincoln's carriage was still in Washington.

Old Hickory and the Pirate

The Travels of Marco Polo...and Friends

Phineas is knocked unconscious, flat on his back. When he wakes, he's lying face down. Did someone turn him over?

Bogg mispronounces "Atoll."

An Arrow Pointing East

After battling Bogg for first passage across the bridge, Little John backs off to his side of the river and doesn't cross at all.

Merry Christmas, Bogg

Bogg uses gold coins he got in 1892 to play poker in 1776. Don't the Redcoats wonder what "United States of America" means?

The 1776 carolers sing "Deck the Halls," a song which didn't gain its English lyrics until 1862.

Buffalo Bill and Annie Oakley Play the Palace

The Trial of Phineas Bogg

Sneak Attack

Bogg and Jeffrey "sneak" into the back of the truck while a taxi is in plain sight right behind it. No wonder they get caught.

Why does the fact that the radioman doesn't believe the Japanese are planning a sneak attack make a believer out of Jackie?

Would Phineas really stand there talking about who gets to save MacArthur's life?

Voyagers of the Titanic

What Molly Brown actually says is that, if Bogg could afford that doodad he has on his belt, he must be traveling first class. Bogg interprets that to mean that she's seen an Omni before, but it could easily mean the Omni simply looks expensive to her.

Pursuit

Destiny's Choice

All Fall Down

The stewardess warns the passengers of the emergency, yet we see them all reading magazines before they pass out. Isn't that a little cold in the middle of a hijacking? Or are they reading the instructions for an emergency landing?

Barriers of Sound

Jack's Back

As the series winds down, you can see Jeffrey's shirt growing much too small on him, as well as a rip in Bogg's shirt. Apparently, the studio didn't want to spend any money by this point on additional wardrobe.

It looks like Nellie tries to cock the hammer on her derringer, but she fails.

Jeffrey talks about how much he loves 'Sherlocks Holmes.'

Conan Doyle says he has not yet been able to deduce the fact that the attacker's footprints lead only to the scene of the crime and Bogg's lead only away. What he means is that he's not been able to deduce the meaning of the fact; he has the fact down cold.

If Inspector Lestrade is a real person, would Conan Doyle really use him as a character in A Study in Scarlet? Especially when portrayed in such an unflattering light?