Incorrect. It says that about half of the ice sheet melts at some point during the year.
The ice sheet is 660,000 square miles. So basically, the area that had some melt in 2018 is around the same size as Texas.
If you look at the FULL graphic, and read the FULL article, you'd know that what they're saying does not support your skepticism. E.g. they point out how there were multiple massive melt spikes during the summer, which were among the largest on record; how the glaciers are flowing faster now than in the past; and as a result, even with above-average snowfall in 2018, the ice sheet won't change much this year.
Oh, and the NSIDC are the ones that produced the data used for this chart....
I
hate to disappoint you, but talk about Greenland losing ice mass is not going to stop any time soon, because Greenland's ice sheet will not stop losing ice mass any time soon.