Charles Schulz's simplified style confused some printers at first, leading to "corrections" that were more usually the opposite - erasing a character's eye after mistaking it for a misplaced ink blot, for example.
A strip of Prickly City had a glaring miscoloration that made the punchline hard to understand. The strip ended with Winslow being beat up between panels, but in the final panel, his color palette has been switched with that of Carmen. You can tell it's Winslow because he has a snout and tail.
This happens a lot in colorized strips. Full-color strips Monday-thru-Saturday are still a novelty that only some papers bother with, so for the most part these strips are produced only in black and white just like in the old days, and the colorization is farmed out by the syndicate. It's not publicly known who they farm it out to, but there's strong support for the theory that English is not their native language. Exceptions mainly include big-name strips that are already produced by entire studios, and Non Sequitur, which is not colorized at all at the artist's insistence.
From about September 2000◊ to January 2001◊, Garfield was very jagged and angular in every aspect, particularly Garfield's face. This could've owed to a new inker or penciler taking over and not being as familiar with the "house" style.
In a couple of Pearls Before Swine strips, Rat's nose was much longer than usual.
Pearls Before Swine also parodied this once, in which the colorist deliberately colored the last panel wrong to be an ass to Stephen Pastis.
When Greg Howard handed off illustrating the American Sally Forth comic to Craig Macintosh (Howard kept writing for a while), readers protested that the new artist made the characters too thin. Macintosh began emulating the original style soon after.
In one Calvin And Hobbes strip Calvin is drawn with six fingers on one hand.
