[Bug Report] [Cascader cascade selector] expand-trigger: hover, expansion switch of secondary menu BUG

[showbestriven]

Element UI version

2.6.1

OS/Browsers version

win10/chrome 71.0.3578.98

Vue version

2.6.8

Reproduction Link

https://jsfiddle.net/5vwk0j9h/

Steps to reproduce

先鼠标移到父级一，
然后再移动到父级二

What is Expected?

鼠标移动到 父级一， 显示 父级一的子级
然后 鼠标移动到 父级二， 父级一的子级消失

What is actually happening?

鼠标移动到 父级一， 显示 父级一的子级
然后 鼠标移动到 父级二， 父级一的子级【未消失】

[element-bot]

Translation of this issue:

Element UI version

2.6.1

OS/Browsers version

Win10/chrome 71.0.3578.98

Vue version

2.6.8

Reproduction Link

https://jsfiddle.net/5vwk0j9h/

Steps to reproduce

Mouse to parent 1 first.

Then move to parent 2

What is Expected?

Mouse to parent 1 to display children of parent 1
Then the mouse moves to the parent level 2, and the child of the parent level 1 disappears.

What is actually happening?

Mouse to parent 1 to display children of parent 1

Then the mouse moves to the parent level 2, the child of the parent level 1 [not disappearing]

[SimonaliaChen]

fixed in #15611