The source of the claim is from the Chinese internet forum Sina.com. That forum is known for its anti-American (or anti-anything that is not sympathetic to Beijing!
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)
In short, that type of sharp manoeuvre is common for any ship that is on trials. As the Nimitz only recently completed its refueling of its nuclear reactors cum some refurbishment (?), it is naturally for the USN to subject the newly-charged carrier for some test before re-introducing into the Fleet.
Therefore, any pics of any US airborne or naval craft that shows it in some 'dangerous moves' is easilly hijacked by such forums like Sina who will take every opportunity to blast the US!
Why? To show that the PLA is an army that acts
'professionally' and
'respectfully' (ironically this is the same army that massacred and crushed its unarmed civilians in 1989)
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in contrasts with the US military.
You guys should read the posts at Sina.com, full of xenophobia sentiments and nationalistic comments!