Stopping light - will it cause a gravity anomaly?

Harvard Gazette
"Two years ago we slowed it down to 38 miles an hour; now we've been able to park it then bring it back up to full speed." Lene Hau isn't talking about a used motorbike, but about light – that ethereal, life-sustaining stuff that normally travels 93 million miles from the sun in about eight minutes.

That should show a huge gravity anomaly n^4G/c^4 if my idea is actually followed by Nature.

Hau's team stopped light for one-thousandth of a second. Atomically speaking, "this is an amazingly long time," Hau notes. "But we think it can be stopped for much longer."

This was only a milli-sec - but an effect should be there (here it would be a normal gravity attraction blip because no negative EM energy density). Of course the EM energy density here is tiny.
Note the objections are for propagating far EM fields - not clear what happens for near EM fields.