To save others having to read through the thread, this appears to be caused by this bug:
https://bugs.chromium.org/p/chromium/issues/detail?id=148880...
Roughly, as you type the omnibox has various heuristics to prevent the order of results shuffling when you type each letter. In this case the search result for "sentry.i" has its position preserved instead of the intended "url-what-you-typed" taking priority over search.
No conspiracy needed here, just over complicated design that comes from trying to munge two different functionalities into one UI element.
