Application runs on --live-reload but not on release mode

I am getting ready to post my app. Unfortunately, it is working fine only using debugging versions but not production ones.

If I run the app using ionic run ios -lcs --device --debug it works fine.

However, when I run the app without the -lcs parameter and debug I’m getting a blank screen with the following error on the web inspector:

Module parse failed: ../node_modules/mydatepicker/src/my-date-picker/my-date-picker.module.ts Unexpected character '@' (6:0)
You may need an appropriate loader to handle this file type.
| import { InputFocusDirective } from "./directives/my-date-picker.input.directive";
| @NgModule({
|     imports: [BrowserModule],
|     declarations: [MyDatePicker, InputFocusDirective],

I tried to research about which proceses differs between building dev and building prod but can’t find anything concrete.

Any ideas on what could be happening? Thanks!