Issue #281 has been updated by Shyouhei Urabe.

Status changed from Open to Rejected

Yes.  That's an expected behavior.  Time.parse ignores what cannot be a time representation (ex. Time.parse("it's 18:00") #=> Time object of 18:00 today), and Time.parse("") is designed to be Time.now, hence the result.
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http://redmine.ruby-lang.org/issues/show/281

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