I agree the timing is funny -- after the Novichok story more or less fell apart.
Funny, too, that it came shortly after Trump insisting multiple times that he wants the US out of Syria (see http://nymag.com/daily/intelligencer/2018/04/trump-hates-timelines-yet-gave-syria-exit-6-months-report.html):
"In an aside during what was supposed to be a speech about infrastructure last week, President Trump announced, “We’re coming out of Syria, like, very soon. Let the other people take care of it now. Very soon — very soon we’re coming out.”
"This was at odds with what basically every other U.S. official has said over the past few months, so many hoped this was just one of the president’s meaningless public musings. But Trump reiterated his desire for a rapid withdrawal of U.S. troops from Syria during a press conference on Tuesday, even as senior U.S. officials in the campaign against ISIS were making the case for remaining there indefinitely elsewhere in the capital.
"Senior administration officials claim that during a meeting with the National Security Council several hours later, Trump agreed to stop insisting on immediate withdrawal after military commanders said they needed more time to wrap up their mission. However, he instructed them to wrap up the operation so the 2,000 troops on the ground in Syria can come home in a matter of months."
So now we are reminded that Syria is the bad guy, and Russia is the bigger bad guy. Got it.