tarr94 (12/5/2016)
Thank you for the suggestions so far!There have been questions about whether the size increase relates to the data or log file. I can confirm that the sys.master_files.size we're looking at is a data file (type = 0, .mdf files)
This could be caused by index maintenance. If, for example, the fragmentation on a large index finally reached a tipping point, the rebuilding of a large clustered index could cause some serious growth in the MDF file because the original CI is preserved until the new CI has been successfully created and committed.
--Jeff Moden
Change is inevitable... Change for the better is not.