The Parkhead club released a statement yesterday afternoon revealing that banners would be allowed into McDiarmid Park after all.
But the Perth club and Police Scotland immediately dismissed that and insisted no U-turn had been agreed and the ban would still stand.
In their statement Celtic claimed to have held talks with St. Johnstone about reversing the decision.
But it turns out that Hoops security chief Ronnie Hawthorn had mistakenly called Inverness Caledonian Thistle instead.
Hawthorn thought he was speaking to his Saints counterpart Peter Mathieson.
But in actual fact he was speaking to Peter MacCallum in the Highlands - where Neil Lennon's team play on Sunday.
An Inverness insider said: "Peter Mathieson and Peter MacCullum must have been right next to each other on a mobile phone.
"Peter MacCallum must have been asked if it was okay for Celtic fans to take banners to the game and he would have said it was fine thinking it was Sunday's match.
"The whole thing has been a big mix-up. It is quite confusing."
Celtic, St. Johnstone and Police Scotland were holding further talks about the issue today.
The Scottish champions still hope the ban will be lifted.