Unicode parsing error: Invalid unicode codepoint (fffd), cannot represent as ASCII/Latin-1

[alexeychikk]

Im following the official Squash the Creeps godot tutorial but using TypeScript.
In the Godot Engine I see the following error:

  Unicode parsing error: Invalid unicode codepoint (fffd), cannot represent as ASCII/Latin-1

Here is my repo where this is reproducible:
https://github.com/alexeychikk/ts-godot-squash-the-creeps

You'll need to:

npm i
npm run ts

[nmerget]

I got the same issue in my test repo. I found this.
Maybe it is just an issue from using the wrong String somewhere