Unhandled rejection Error: Invalid arguments

I'm getting this error while trying to force webpack dev server to write files it serves for webpack itself. Most of files are successfuly "written" into a "dest" directory. But it fails at some point with following stack trace, which actually doesn't help to understand a problem:

``` bash
[11:57:28] [write-file-webpack-plugin] asset: ./main-9c5ec44d5dd566b19756.js; destination: ./dist/main-9c5ec44d5dd566b19756.js [written] (6.39 MB)
[11:57:28] [write-file-webpack-plugin] asset: ./main-9c5ec44d5dd566b19756.css; destination: ./dist/main-9c5ec44d5dd566b19756.css [written] (479.77 KB)
[11:57:28] [write-file-webpack-plugin] asset: ./main-9c5ec44d5dd566b19756.js.map; destination: ./dist/main-9c5ec44d5dd566b19756.js.map [written] (7.64 MB)
[11:57:28] [write-file-webpack-plugin] asset: ./main-9c5ec44d5dd566b19756.css.map; destination: ./dist/main-9c5ec44d5dd566b19756.css.map [written] (106 B)
Unhandled rejection Error: Invalid arguments
at filesize (/Users/example/project/node_modules/filesize/lib/filesize.js:50:10)
at /Users/example/project/node_modules/write-file-webpack-plugin/dist/index.js:192:128
at /Users/example/project/node_modules/write-file-webpack-plugin/node_modules/lodash/_createBaseFor.js:17:11
at baseForOwn (/Users/example/project/node_modules/write-file-webpack-plugin/node_modules/lodash/_baseForOwn.js:13:20)
at /Users/example/project/node_modules/write-file-webpack-plugin/node_modules/lodash/_createBaseEach.js:17:14
at forEach (/Users/example/project/node_modules/write-file-webpack-plugin/node_modules/lodash/forEach.js:38:10)
at Compiler. (/Users/example/project/node_modules/write-file-webpack-plugin/dist/index.js:166:35)
at Compiler.applyPlugins (/Users/example/project/node_modules/tapable/lib/Tapable.js:26:37)
at Watching._done (/Users/example/project/node_modules/webpack/lib/Compiler.js:78:17)
at Watching. (/Users/example/project/node_modules/webpack/lib/Compiler.js:61:18)
at Compiler.emitRecords (/Users/example/project/node_modules/webpack/lib/Compiler.js:282:37)
at Watching. (/Users/example/project/node_modules/webpack/lib/Compiler.js:58:19)
at /Users/example/project/node_modules/webpack/lib/Compiler.js:275:11
at Compiler.applyPluginsAsync (/Users/example/project/node_modules/tapable/lib/Tapable.js:60:69)
at Compiler.afterEmit (/Users/example/project/node_modules/webpack/lib/Compiler.js:272:8)
at Compiler. (/Users/example/project/node_modules/webpack/lib/Compiler.js:267:14)
at /Users/example/project/node_modules/async/lib/async.js:52:16
at Object.async.forEachOf.async.eachOf (/Users/example/project/node_modules/async/lib/async.js:236:30)
at Object.async.forEach.async.each (/Users/example/project/node_modules/async/lib/async.js:209:22)
at Compiler.emitFiles (/Users/example/project/node_modules/webpack/lib/Compiler.js:235:20)
at MemoryFileSystem.(anonymous function) [as mkdirp] (/Users/example/project/node_modules/webpack-dev-middleware/node_modules/memory-fs/lib/MemoryFileSystem.js:283:10)
at Compiler. (/Users/example/project/node_modules/webpack/lib/Compiler.js:229:25)
```

Settings are all corresponding to a guide provided in README.md. devServer has an outputPath which equals to webpack.output.path.

Any thoughts?