The Odhams 'Power Comics' remain my all-time favourites but when they made mistakes, they made some real clangers.
When reprinting Marvel strips, Odhams were supplied with black and white copies of the artwork and, presumably, some sort of colour guide, probably in the form of the original comics. That colour guide wasn't always adhered to. The mistakes could sometimes be minute, but a few times... well, see the cover of Terrific No.20 above, with Captain America charging into battle bare legged. They quite often made the mistake of giving him bare arms but this was something else. For a Living Legend of World War 2 who was trying to retain the respect of those around him, hot pants were not a good look.
In the background, you'll notice that Thor's hoping for a tan as well.
I'm also showing the original printing here from Avengers No.15. I hope you'll forgive the tatty cover. This was the third Marvel comic I bought and I hadn't quite developed the habit of trying to keep them in near mint condition when I was eight.
Another big clanger, but not quite as funny, had taken place a year earlier in 1966, with The Hulk's first cover appearance on Smash! As most comic fans know, in his first issue in America in 1962 The Hulk had grey skin, but as it didn't print consistently they changed it to green from issue 2. Presumably no one told Odhams...
And to top it off, The Hulk had a preference for white nail varnish. Who'd have guessed? "The strangest man of all time!!" Indeed, and he's wearing a yellow dress.