With The Flash film losing its director over creative differences, there seems to be some uneasiness amongst the rest of the DC Cinematic Universe, including the upcoming Aquaman.
According to BirthMoviesDeath.com sources, Director James Wan is possibly exiting Aquaman, due to "a tremendous amount of trepidation" about the project. With Batman V Superman: Dawn of Justice not getting the critical or commercial response they had hoped for (though it has raked in $855,322,593 worldwide), Warner Bros. has doubled down on all the DC projects and is taking a much more active role in their development.
A good point is made that Wan doesn't really need Aquaman, as he has both The Conjuring 2 and Lights Out coming out later this year, both of which will most likely be a good return on investment for Warners. With all the chaos that surrounds the DCU at this moment in time, he might just prefer to sit this one out. Hopefully, that isn't the case, but only time will tell.