Version: 56.0.2890.0
OS: Android

After bookmarking a site with offline pages enabled, and going offline.  Visiting the url loads and the "bookmark" offline copy, but a "last_n" version is created at the same time.

What steps will reproduce the problem?
(1) Start Chrome with offline pages enabled
(2) Visit a site, wait for it to load, bookmark it
(3) Go offline
(4) Open a new tab and go the url in step #2
(5) Visit chrome://offline-internals

What is the expected output?

No new copies are created.

What do you see instead?

A "last_n" offline copy is created.

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