I don’t think 848 was accompanying 002. It’s more likely 848 was simply passing by like the guy who took the photo.
002 would be in a restricted area during her sea trial, thus it is unlikely a minesweeper accidentally meet up with her. From many previous sea trial photo, including that of CV16 Liaoning, we have seen many different types of naval ships accompany her, which includes DDG, FFG, submarine rescue ship.
When 002 sailed out for this sea trial, another minesweeper #811 was at the scene probably acting as sentry/ escort, thus it is not an accident that another minesweeper #848 doing escort duty.
The choice of minesweeper and submarine recue ship for escort duty is purposeful. This is a peace time sea trial, there is no need for DDG or FFG. Minesweeper and submarine rescue ships have better under water equipment, and is more than adequate than a DDG or FFG in case there is an accident of an aircraft in water during the sea trial involving air operation.
Appearance of a couple of minesweeper point towards that 11th mine sweepers squadron based in Dalian has been given the escort task.