We commonly see this while doing builds. The linker creates a new .dll or .exe and a corresponding .pdb, and it takes a while for the anti-malware (and other IT-mandated surveillance software) to do their scans of the new files, especially since the build is largely I/O bound anyway. Meanwhile, in a subsequent build step, the manifest tool tries to update the manifest information in newly-created binary, but it fails because the aforementioned software still has the files locked for the duration of their scans.
After upgrading the toolchain, we've seen that the manifest tool now backs off and retries a couple times before giving up. Most of the time, that's enough to make the build successful, but not always.