Uncaught Error: Expected to find a document already present for removed

When I try to log into app, the error I get in client console (chrome dev tools) is this:

Uncaught Error: Expected to find a document already present for removed mongo.js?69942a86515ec397dfd8cbb0a151a0eefdd9560d:253

and the login is halted: the loading gif from the accounts-google package shows and the loading never ends.

I however get no errors in server console. Unfortunately, the error gives me little understanding as to where to even start debugging my app from.

I have gone through the portion where the error is thrown in the mongo.js file, but I don’t get what’s going on there from it either.

Since I do not have any idea where I am going wrong, this is the link to the project repository. I’m currently looking for pointers, as to what might be causing the error, in router or collections, etc