I found this time travel case mentioned in the book The Little Giant Book of Eerie Thrills and Unspeakable Chills which is written by Ron Edwards, C. BH. Colby and John Macklin.
In 1932, newspaper reporter J.Bernard Hutton and photographer Joachim Brandt were assigned to do a feature story on the Hamburg, Germany, shipyard. They drove to the huge complex, interviewed several executives and workers, and completed the assignment by late afternoon.
Upon leaving the area, the two newsmen heard the unmistakable drone of aircraft engines which caused them to look up to the sky seeing it filled with warplanes. Then they heard the city's anti-aircraft batteries opening fire as bombs began exploding around them.
Moments later, the area was a raging inferno as fuel tanks were hit. Warehouses were collapsing from high explosives and dock cranes were twisted into pretzels.
Hutton and Brandt realized this was no drill.
They rushed to the car as anti-aircraft gunners began scoring hits on the bomber formation overhead. At the gate, Hutton asked a security guard if there was anything they could do to help but was told leave the area immediately.
Hutton and Brandt were confused when they drove into Hamburg. The sky had turned dark during the attack, but now it was clear and the city was serene. The busy streets were not indented with craters and the buildings were intact. No one seemed concerned as they went about their daily business.
Hutton and Brandt stopped the car and looked back towards the shipyard. Now they received another shock because they saw no black ribbons of smoke rising into the sky and no damaged buildings. What was happening?
Back at the newspaper office, Brandt's pictures were developed and the two men got yet another surprise.
Brandt had continued to shoot film throughout the air raid, but his photographs showed nothing unusual. The shipyard looked as it did upon their arrival that morning. There was no evidence that a rain of bombs from enemy planes had destroyed the area, as they had witnessed.
The editors studied the photographs and wondered why Hutton and Brandt insisted they had been involved in an air attack. He dismissed their story and decided that they had probably stopped at a tavern for a couple of drinks on the way back to the office.
Just before World War II Began, Bernard Hutton moved to London. In 1943, he saw a newspaper story about a successful raid by a Royal Air Force squadron on the Hamburg shipyard. He felt a cold shiver along his spine as he studied the photos. The scene of destruction was exactly as it appeared during his visit with Brandt in the spring of 1932.
There was only one thing different - Hutton and Brandt had witnessed the event 11 years before it happened.