It will be a lot easier for anyone to help you out if you simply share your code instead of images of your code. You can base your demo off of the Jsfiddle template included in the readme, if it's easier for you.

This may help you: https://vuejs.org/v2/guide/reactivity.html#Change-Detection-Caveats

@posva if i watch the var named 'varieties' it worked well

FYI, just pasting the code does not satisfy the requirement for a reproduction. Please follow the Issue Reporting Guidelines and provide a minimal JSFiddle or JSBin containing a set of reproducible steps that can lead to the behavior you described.

Why is this required?

@yyx990803 The reproduction jsfiddle is now interactive and I'm stumped as to why it behaves the way it does. :/

Maybe it's my dizzy sunday head, btu this looks like a bug?!?

The newly pushed watchers caused by state changes inside updated hooks haven't been called at all.
In core/observer/scheduler.js L83 to L86, the queue is cleared after all updated hooks have been called.

Thanks all you guys