Bug or feature? Independent parallel builds sometimes throw eperm errors related to file-map.json

[JonMarbach]

I'm starting this as a discussion, but it could become a bug report depending on the responses here...

After upgrading from a very old version of nx (v10) to 19.4.4, our CI/CD server (GitLab) is reporting sporadic errors like this:
error : EPERM: operation not permitted, rename <path to workspace>\.nx\workspace-data\file-map.json~0208b8a5 <path to workspace>\.nx\workspace-data\file-map.json~0208b8a5 -> <path to workspace>\.nx\workspace-data\file-map.json
My hypothesis for this is that this is caused by separate builds running in parallel - but this parallelism is something we are doing outside of nx (the builds are triggered by CMake because they are part of a larger project.) The targets are independent of one another, but since they live in the same monorepo, they share a .nx folder. My guess is that separate instances of nx are simultaneuosly updating the file-map.json and clashing. In case it's relevant, I am using the package-json plugin for project discovery.

(If you are wondering why I am using 19.4.4 it's because I was having trouble with projects not being found and I had seen a few bug reports all saying that 19.4.4 is the last version that worked for them.)

I am trying out the run-many feature to regain parallelism but what we lose is that we now need to build all of our projects via a single CMake target which is overkill.

Thoughts are welcome!