Chrome Version:  63.0.3239.116/ 10032.75.0  stable-channel Daisy,Reks and Candy
OS: Chrome

URL : https://www.google.co.in/search?hl=en&tbm=isch&source=hp&biw=1366&bih=654&ei=vOo4Wp67KYHJvgTAyJe4CQ&q=images&oq=images&gs_l=img.3..0l10.6137.8415.0.9221.10.10.0.0.0.0.414.1157.1j3j1j0j1.6.0....0...1ac.1.64.img..4.6.1151.0...0.uSeKIr88Mfw

What steps will reproduce the problem?
(1)Sign into User ->Go to above URL for 'Images' page 
(2)Now select any Image and select 'save as image' option and observe image in Notification overlay
(3)Now immediately select other Image and select 'save as image' option -> click on 'Save'(First notification should not get vanish) -> observe blink of second image notification overlaps on First image Notification (Please refer Video and Screenshot)

Expected: 
a)No such notification blink should be seen
b)Second image notification should not overlap on First image Notification i.e. second Image notification should be seen at top of First image Notification

Actual: Instead blink of second image notification overlapping on First image Notification is seen

This is Non-Regression Issue seen from M-55

@yoshiki : Please confirm the Issue
 

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