I think this bond sell off really took off when President Trump called for negative rates. Besides China, Japan(which is currently the largest debt holder due to china selling) actually mentioned selling US debt due to fear of weak US dollar and I think that fear is picking up greatly in the current environment.

https://www.wsj.com/articles/uncle-sams-trillion-dollar-customer-is-having-its-doubts-1519727406

I think if Trump really pushes for negative rates/weaker dollar, this bond sell off will probably continue unless FED surprises us then maybe a bounce/pull back first.

As for the uncontrolled big bond sell off, what would be the reason for that? Curious if there are other events needed to take place before that happens to warn us, as that is quite concerning if it just happens at a seemingly random time