I presume they are not doing an EVA to have a look. As long as they don't seem to have any problems associated with it, why take the chance. EVAs come with a certain amount of risk. But it would be nice to know what caused the noise. Perhaps the next Soyuz crew rotation flight could try to look at it during the approach and fly-around.

These things always seem so simple to us who are not involved with the complex logistics of such an operation. "Just go up there and fly around" we say, "nothing to it". I'm sure it's a lot more complicated than that. You have to be concerned with a number of safety issues, like accidentally bumping into it, and keeping the RCS gasses from getting all over the solar panels, etc, and other things we would not think important.