strange behaviour of some modules when required from GitHub

As you may know, I'm currently developing an "Analog Clock Construction Kit" which (currently) heavily relies on external modules required from GitHub.

However, there are modules which behave differently depending on whether they are actually loaded from GitHub (by the Web IDE) or manually inserted into the code using the following "trick"

let exports = {}
  <<<< insert module here
let XXX = exports

as a replacement for

let XXX = require('<GitHub URL>');

Two modules are affected - and I don't know why:

• rounded clock hands - work fine when inserted manually, but produce wrong graphics when loaded from GitHub
  
• smart clock size calculator - works fine (even if loaded from GitHub), but produces an annoying error toast (Error: Unreachable point. logically broken. in https://raw.githubusercontent.com/rozek/banglejs-2-smart-clock-size/main/ClockSize.js) in the WebIDE
  
  

Does anybody have any ideas how to solve these problems?