After running a deployment the error message 'User security information cannot be properly imported without setting UserInfoDateTime option to ImportAll.' appears.
Despite setting the 'Security information in the deployment' to 'All' the message still appears, though the deployment still goes through. I've changed the setting to 'Role Definitions Only' and - guess what - it still appears. If the selection is reset to 'All' it is still there. The reason for resetting it was to check that it was actually being set, but from the tests it appears that the value is never actually passed.