Synthetic "Connection timeout", but with a page?

[AntonioSousa]

I have run into a situation where there's a site that is having problems, but with strange data being recorded by Dynatrace:

So, I have a page with the redirect, request, and also a long OnLoad. The long OnLoad is strange, the page dimension is not what is expected, and it did not load correctly.
But why a Connection timeout? I have two possible ideas, but anyone have additional ones?

• Chromium Browser typically makes two connections. Might the second one have timed out. Highly unlikely, as a re-run was made.
• Since there's a big OnLoad, something running there that invokes another "document", which connection timed-out.

[AntonioSousa]

Have figured out that it was the second idea, in this case 😁