What steps will reproduce the problem?
(1) Start chrome signed out and with sync disabled.
(2) Navigate to some page (www.youtube.com).
(3) Navigate to some other page (maps.google.com) in the same tab.
(4) Enable sync.
(5) On a different device sync-ing to the same account, open chrome://history.

What is the expected result?
The first page (www.youtube.com) should not show up in sync-ed history.

Whether or not the second page (maps.google.com) should show up is debatable.

What happens instead?
Both pages (www.youtube.com and maps.google.com) show up in sync-ed history as displayed in the second device's chrome://history.