I seem to have similar issue. I’m running a small node of only 3TB, and unfortunately most of that was filled up saltlake. About two months ago, even though my Used space still says 3.0TB, my Average Disk Space Used This Month dropped all the way down to 111.37, with saltlake showing 0 storage and activity, while that 111.37 is split among ap1, us1, and eu1.
Based on what Alexey said in previous threads, I believed that I would still get a full payout for those 3TB on saltlake, but payment just came in and it was only $0.06, with saltlake paying nothing. What really sucks is that I have almost 3TB of saltlate data that isn’t paying anything, and the other three nodes that do work don’t have any free space to add anything.