Document load event not fired in Chrome

Question

We have an application using WebComponents V0 spec. We use Polymer's vulcanizer to put together all our components into a single importable HTML and import it from the main application page (HTML imports). Noticed an issue in Chrome recently (not sure about the version-since) that document doesn't load on the first attempt. On subsequent reloads from cache, the document gets loaded successfully. With cache disabled, the document doesn't load again. The browser tab just keeps spinning and there is no DOMContentLoaded or Load event markers in the network panel.

How do we know what is going on in Chrome? What are the typical steps to be followed when document load is not happening?

Here are the things that I can confirm:

• There is no infinite loop in code. Browser main thread seems to be idle
• There is no pending resource to be loaded in the network panel
• There is no activity on the Performance panel of Chrome devtools
• Tried toggling the polyfill
• Issue seems to happen only when webcomponents are used in the page
• Document's readyState was loading. All other HTML imports on the page had status as complete
• There is no luck with Incognito mode as well