This occurs on canary and TOT, but not on my local build a few days ago. Is this changed in custom tab very recently?

In addition, this is not occurred on Chrome Dev (61.0.3163.13).

I was thinking this, but it was a while ago:
https://chromium.googlesource.com/chromium/src/+/ec7832af966579298a2e9886117a7171d64b8122

But I believe it was actually from:
https://chromium-review.googlesource.com/c/578746
I left a comment.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ab0745ba2d65b6a800660718c797d673956b6bac

commit ab0745ba2d65b6a800660718c797d673956b6bac
Author: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Date: Mon Aug 07 19:26:30 2017

Do not hide URL in CCT when ReaderMode is enabled

https://crrev.com/c/578746 accidentally modified CustomTabActivity.java,
and URL in CCT would be hidden when ReaderMode is enabled.
It is reverted now.

Bug:  751122 
Change-Id: If8615e3dcef070bb9a6cfd204e2a3d3618ea9ec4
Reviewed-on: https://chromium-review.googlesource.com/602809
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492380}
[modify] https://crrev.com/ab0745ba2d65b6a800660718c797d673956b6bac/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java