When a .po folder contains some build files (.mo, .po~, template.pot), then the assets that are published contains invalid entries. For example:

$ cat src/www/assets/core/project/project-registration-po-0-53271732b94aebc8821a.js
(window.webpackJsonp=window.webpackJsonp||[]).push([[7],{63:function(e,o){throw new Error("Module parse failed: Unexpected character '�' (1:0)\nYou may need a
n appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders\n(Source
code omitted for this binary file)")}}]);

The build of assets should not try to compile other files than .po.