[Bug Report] Notification component -> this.$notify position problem

[yuxino]

Element UI version

2.9.1

OS/Browsers version

macos

Vue version

2.6.10

Steps to reproduce

https://codesandbox.io/s/130myl2jk7

click button u can see tooltip overlaps and position is wrong

What is Expected?

https://codesandbox.io/s/2k9253ljn

click button u can see tooltip not overlaps and position is correct

What is actually happening?

tooltip overlaps and position is wrong

Description

@jikkai I submit this bug about 1 year ago, but still nobody fix this bug. last time i had been closed by the reason is Duplicate of #7389. Note it is not a duplicate issues of #7389 . The reason for this bug is somebody modify the function arguments's properties .

See the reproduce link, it's my original object

When i call this.$notify, my object has been modified

These new attributes will affect the behavior of notify component.

Please clone a new object to do that . don't do something like this and this ...

Although modifying an incoming parameter not an anti pattern, but it's a bad practice :(