WSUS Disk Space is rapidly depleating

We originally gave WSUS 40 GB of disk space to store updates locally. This was perfectly fine for the longest time, but recently WSUS has been eating up whatever space we give it. We've increased the amount to 85 GB and within days, the space is gone. I have declined all unnecessary updates and run the Server Cleanup Wizard, but the next day, the freed space (15 GB) was all but gone. We have it set to only download once updates are approved and no new updates have been approved during the time that WSUS ate up the free space. We're only downloading English language updates and are only automatically approving WSUS product updates and revisions to updates.

Any ideas on what could be causing so much free spaces to disappear?