Crash on adding existing file from subdirectory

Upon opening an existing project (no .pro file, only .creator and associated), if this project contains files from subdirectories, Qt Creator crashes.

Same thing happens when starting a fresh project from scratch: I can add files which comes from the root of the project, but not if they are from a subdirectory. They get added to the Project.files list, but creator crashes, and reopening the project crashes.