iOS Version: 10.3.3,11.3
Device: iPhone

Precondition:
1. Enable ui-refresh-phase-1 in chrome://flags

Steps to reproduce:
1. Launch chrome 
2. Tap on Tab Switcher.
3. Tap on  + button  quickly 7 to 8 times

Observed results:
Fake omnibox and Omnibox are displayed in NTP

Expected results:
Omnibox should be displayed only once.

Number of times you were able to reproduce: 3/5
Bug reproducible after clean install: Yes
Bug reproducible after clearing cache and cookies: Yes
Bug reproducible on Chrome Mobile on Android: NA
Bug reproducible on Dolphin/Safari/Firefox: Safari : NA
Bug reproducible on the current beta channel build : NA in M66
Bug reproducible on the current beta channel build : Yes in M67

Video :
https://drive.google.com/file/d/1UFfZ7k_j7yG7z9VEeS8n5PUl5GKf9vI9/view?usp=sharing