I installed version 18.104.22.168 yesterday. Today I got an alert Low Disk Space on both drives C: and D:
Free Space: 0.0 bytes
Used Space: 0.0 bytes
Capacity: 0.0 bytes
File System: NTFS
Both drives are well under 50% utilization. The alert is set for the default 80% trigger. As far as I can tell there's nothing noteworthy in the windows event log or SQL log that occurred around that time.
OS is Windows 2008 R2 Enterprise 64-bit running SQL Server 2008 Enterprise 64-bit. Dell PERC/6 controller with RAID10 array.