Deno bundle duplicating variables

Using Deno 1.26.2

I am trying to bundle https://github.com/Savory/Danet-Starter using

deno bundle run.ts standalone-starter.js

deno bundle run.ts standalone-starter.js

However, the generated

standalone-starter.js

standalone-starter.js

contains duplicated variable declaration, resulting in

error: Uncaught SyntaxError: Identifier 'mod' has already been declared

error: Uncaught SyntaxError: Identifier 'mod' has already been declared

while trying to use

deno run standalone-starter.js

deno run standalone-starter.js

.

Did I do something wrong or is it a bug ?