As per the comment #3 in  Bug 912151 

App Version: 73.0.3637.0 canary
iOS Version: 11.4.1
Devices: iPhone 8,

Prerequisite:
Make sure #slim-navigation-manager is enabled in chrome://flags.

Steps to reproduce:
Launch iOS Chrome
Navigate to any webpage ex. https://en.wikipedia.org
Navigate to back to NTP using edge swipe gesture
Repeat steps 2 and 3
Navigating back from web page to NTP a second time, a black screen is visible

Note: Only observed when navigating by edge swipe.

Observed results:
Black screen is displayed when navigating between NTP and a web page in slim nav

Expected results:
Black screen should not be displayed when navigating between NTP and a web page in slim nav

Link to Image/Video:
https://drive.google.com/open?id=1tpOyE5jdTjzEJq7Jp3emmbplJ3PcmTAv