It wasn't unknown for people to read out of date magazines and newspapers in Coronation Street back in the '60s, '70s and '80s (it probably still happens nowadays). When you remember the time lapse between the recording and screening of each episode, it was inevitable that if you glimpsed the headline on a newspaper being read by a character, or a magazine cover, it was going to be a few week's old.
But in 1982 an eagle eyed viewer spotted dastardly doings at The Kabin:
From the Daily Star, letters page, Wednesday, July 28, 1982:
I wonder whether anybody else noticed how out-dated Rita Fairclough's magazines are in Coronation Street. Last Wednesday (July 21) Mavis held one dated February 27.
M.C. Daventry, Northants.
The Star got on to Granada who replied:
"Daily Star readers are certainly sharp-eyed to spot our mistake. With a million and one details to attend to in the programme, this one escaped our notice."
"Ooh, Rita, do you really think it's right selling out of date magazines?"
"Shurrup, Mavis, Len's got a deal wi't wholesalers, gets 'em for next to nowt and folk round 'ere are that puddled they'll never notice!"