According to this film, Dracula has spent the 10 years between 1804 and 1904 in a remote Chinese village in an alternate form as the now-vampiric High Priest Kah; this contradicts all of the events from the previous eight Hammer "Dracula" films.
In the film's first fight scene, as the 7 Brothers are rushing forward to meet their enemies, one of them stumbles over a sword that is lying on the ground, apparently from a previous take.
When the Undead rise up from the cemetery, the soil under the grass is green floristry foam.
During the fight with the bandits in the film, an archer shoots one of them in the neck. The angles of the entry point and exit point of the prop arrow are clearly different.
The vampire's golden burglar style mask that was lost 100 years earlier would not have survived out in the elements intact 100 years later.
At the reception in the British Trade Consulate, a portrait of Queen Victoria is prominent in the background. The setting for this scene is China in 1904 so the portrait would be of the then current monarch - King Edward VII - not one of Queen Victoria.
One of the taglines on the film's U.S. theatrical release poster says "Black Belt vs. Black Magic!". The martial arts ranks of colored belts are used in karate, which is Japanese in origin. The Chinese characters portrayed here practice kung fu, which originated in their home country.