Inconsistent error using Bootstrap

I am new to front-end development in general.
My web application works as intended but for one problem. After adding Bootstrap, I get the following error on browser console. The worst part is, I get it sometimes and sometimes I don’t.

Source map error: Error: JSON.parse: unexpected character at line 1 column 1 of the JSON data
Resource URL: http://localhost:3000/
Source Map URL:

My application is a single page application and everything is practically on client side. The only reference to Bootstrap is in main.js:

import "bootstrap/dist/css/bootstrap.css";
import { Template } from 'meteor/templating';
import './main.html';

My ‘meteor list’ reads like the following:

autopublish            1.0.7  (For prototyping only) Publish the entire database to all clients
blaze-html-templates   1.1.2  Compile HTML templates into reactive UI with Meteor Blaze
ecmascript             0.14.3  Compiler plugin that supports ES2015+ in all .js files
es5-shim               4.8.0  Shims and polyfills to improve ECMAScript 5 support
insecure               1.0.7  (For prototyping only) Allow all database writes from the client
jquery                 3.0.0  Manipulate the DOM using CSS selectors
meteor-base            1.4.0  Packages that every Meteor app needs
mobile-experience      1.1.0  Packages for a great mobile user experience
mongo                  1.10.0  Adaptor for using MongoDB and Minimongo over DDP
reactive-var           1.0.11  Reactive variable
shell-server           0.5.0  Server-side component of the `meteor shell` command.
standard-minifier-css  1.6.1  Standard css minifier used with Meteor apps by default.
standard-minifier-js   2.6.0  Standard javascript minifiers used with Meteor apps by default.
tracker                1.2.0  Dependency tracker to allow reactive callbacks
typescript             3.7.6  Compiler plugin that compiles TypeScript and ECMAScript in .ts and .tsx files

By now I have installed, uninstalled and reinstalled all the three - jquery, popper.js and bootstrap with various options but I am clueless.

Any help will be appreciated.