Angular 4 testing - [object ErrorEvent] thrown

I'm in the process of completing the test bed for my angular application. But there is an issue in the karma-jasmine testing, which throws an error

[object ErrorEvent] thrown

I updated the node_modules as a solution I found in the following link How do I debug a "[object ErrorEvent] thrown" error in my Karma/Jasmine tests?

But now error throws at random times, sometimes test bed is completed without any fault, sometimes above error triggers. Any suggestions to avoid it permanently?

PS - Let me know in the comments if you need more resources. Thanks!