It doesn't see a devDependencies executable on npm 5.4.1

[ip]

I have a package with this package.json:

{
  "name": "@perevezentsev/decode-video",
  "version": "3.0.0",
  "description": "Decodes video using ffmpeg into raw RGBA32 frames",
  "main": "./built/index.js",
  "scripts": {
    "build": "tsc || true",
    "build:watch": "tsc --watch",
    "test": "tape ./built/**/*.test.js | tap-spec",
    "start": "node ./example/",
    "postinstall": "postinstall-build ./built"
  },
  "author": "Ivan Perevezentsev <ivan.perevezentsev@gmail.com>",
  "license": "UNLICENSED",
  "private": true,
  "dependencies": {
    "@types/node": "^8.0.28",
    "chunking-streams": "0.0.8",
    "fluent-ffmpeg": "^2.1.2",
    "mkdirp": "^0.5.1",
    "png-async": "^0.9.2",
    "postinstall-build": "^5.0.1",
    "rimraf": "^2.6.1"
  },
  "devDependencies": {
    "eslint": "^4.2.0",
    "eslint-config-airbnb-base": "^11.2.0",
    "eslint-plugin-import": "^2.7.0",
    "tap-spec": "^4.1.1",
    "tape": "^4.8.0",
    "typescript": "^2.5.2"
  }
}

When running npm install in a project using this package, postinstall-build is triggered correctly, but npm build script doesn't see TypeScript compiler which is in the devDependencies:

➜  test npm i -S ../video-decoder2

> @perevezentsev/decode-video@3.0.0 postinstall /home/vanya/Documents/prog/1.videonow/test/node_modules/@perevezentsev/decode-video
> postinstall-build ./built

postinstall-build:
  This version of npm (5.4.1) may not be compatible with postinstall-build! There
  are outstanding bugs in certain versions of npm that prevent it from working with
  postinstall-build. See https://github.com/exogen/postinstall-build#bugs-in-npm
  for more information.


> @perevezentsev/decode-video@3.0.0 build /home/vanya/Documents/prog/1.videonow/video-decoder2
> tsc || true

sh: 1: tsc: not found
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN @perevezentsev/test@1.0.0 No description
npm WARN @perevezentsev/test@1.0.0 No repository field.

+ @perevezentsev/decode-video@3.0.0
added 24 packages in 9.097s
➜  test npm -v
5.4.1

Are there plans to fix this for this version of npm?