Compilation on Windows constantly fails with "cannot open program database"

Whenever I compile my project on Windows, compilation randomly fails with:

C1033: cannot open program database 'x:\path\to\source\<profile>-<buildVariant>\.obj\<product>\generatedfiles\...\vc100.pdb'
ERROR: Process failed with exit code 2.

If I continually run qbs about a dozen times, the project eventually gets compiled correctly.

My guess is that multithreaded file access causes one thread to try to access the pdb file while another thread still has an open file handle to it. I tried using -j 1 to no avail.

I don't recall ever having come across this error with qmake or CMake so this is definitely something to do with the manner in which qbs invokes MSVC.