Photos of the faux pas circulated on social media Monday, showing the scene featuring the nine-dash line crossed out with a red “X” along with angry comments.
“Please sack the person in charge of censorship for this movie,” said Facebook user Pham Tan Phong.
Another said: “We cannot accept these blatant acts, especially regarding sensitive things like the current sea disputes”.
Vietnam’s censorship department refused to comment on the issue Monday, and DreamWorks did not respond to a request for comment.
China claims the majority of the South China Sea, often invoking its so-called nine-dash line as a supposed historical justification to the waters, a key global shipping route.
Though some films are barred from viewing in Vietnam, a one-party state where free speech is tightly controlled, others are approved for screening only with significant edits.
The popular 2018 romantic comedy “Crazy Rich Asians” saw a few snips. One of the cut scenes featured a designer bag with a map of the world showing disputed South China Sea islands under Beijing’s control.
This year’s hit “Joker”, starring Joaquin Phoenix, was also trimmed to exclude a scene of supporters rallying around the DC Comics villain — possibly to avoid any suggestion of a popular uprising or personality cult.