READ BEFORE ANSWER: I've already solved this issue. It was a caching issue on the npm servers. Everything works fine after switching to GitHub packages. I've already accepted my own answer.
I have a project, which I want to deploy to elastic beanstalk but sometimes the deploy fails on the npm install script with the following message:
npm ERR! code EINTEGRITY
npm ERR! Verification failed while extracting @my-package@^1.2.0:
npm ERR! Verification failed while extracting @my-package@^1.2.0:
npm ERR! sha512-lQ...HA== integrity checksum failed when using sha512: wanted sha512-lQ...HA== but got sha512-nH...ow==. (4835509 bytes)
It fails even on packages which are severel weeks old.
I’ve tried:
- npm cache clean --force
- npm cache verify
- node_modulesis in- .npmignore
- package-lock.jsonis in- .npmignore
- Writing a mail to support@npmjs.com, but they replying always with some helpless default replies without any solution or intention to help. 
It fails even on new elastic beanstalk instances.
I have no idea how to solve this problem.
EDIT: I've also tried to delete the npm cache while preinstall script, but it doesn't work either.
EDIT2: My repo has no package-lock.json.
EDIT3: My .npmrc file has the following content
      //registry.npmjs.org/:_authToken=${NPM_TOKEN}
      unsafe-perm=true
      package-lock=false
      strict-ssl=false
EDIT4: I think it wasn't clear: It's a private package on the official npm registry. And it doesn't fail always. The current publish process includes several attempts to deploy on aws instance so long as it's succeed.
 
     
     
     
     
     
     
    