Summary
Aquaman and the Lost Kingdom director James Wan suggests that Batman scenes have been cut from the movie.
The original intention for including the Batman scenes was to ensure time continuity in case Aquaman and the Lost Kingdom was released before The Flash. But now, since Aquaman 2 will follow The Flash, it is assumed that the Batman scenes are no longer necessary.
Aquaman and the Lost Kingdom's director, James Wan, revealed in an interview with Empire Magazine (via @FlashFilmNews) that the inclusion of Batman in the movie's scenes has been removed due to a recent update.
Please find the revised content below:
"Likely not. The purpose of those scenes was simply to have a backup plan in case we needed to clarify the continuity of time if our release came first. However, as it turned out, Lost Kingdom premiered after The Flash."
Source: Empire Magazine (via @FlashFilmNews)