According to her, Rob is still attached to the movie
Rob's still with us as far as I know. #QOTD
The Hollywood Reporter, 'Queen of the Desert' producer Cassian Elwes talked about the current status of the movie. THR mentioned in one of questions of the Q&A that Naomi Watts and Rob were no longer attached to the project and Elwes commented about the casting issues. Here's that part of the Q&A:
With Naomi Watts and Robert Pattinson dropping out of Werner Herzog’s Gertrude Bell biopic Queen of the Desert, is the project dead?
It’s been in casting hell, but we feel like we are coming out of it now. I think we’re close to making an announcement.
ETA: An update directly from Cassian Elwes via his twitter account
ETA2: According to Deadline, Nicole Kidman is in talks to replace Naomi Watts, but Rob still stars in the movie.
In the past few months there have been many reports about the film. In August, director Werner Herzog talked about coordinating the actors' schedules being difficult (posted here), but didn't mention Rob and Naomi leaving the project.
We'll wait for that "announcement" to know more and keep you updated.