Phaser 6180MFP ADF Scans result in solid black and solid white pages

I have a Phaser 6180MFP that that for a solid year has been great and until recently has been working without an issue.  The users scan large files in batches of about 50 pages using a scan to network folder arrangement.  The printer only has about 35k on the counter but my assumption is the ADF has a lot more traffic than that.  I cannot seem to locate the scan counter info though.

In any case the printer goes through the scan motions for the 50 pages without error or incident.  The pdf is transmitted to the network folder.  Upon opening the PDF we find that the pages are incomplete.  By that I mean in a 50 page document at some point in the job the page image turns solid black (or white) right in the middle of a page.  All of the subsequent pages in that scan job are also black (or white).  Some jobs the entire scan is solid black or white right from page 1, in others it would scan 10 pages properly, then 10 that are white, then the rest are solid black, and in other cases the whole batch is fine.  This seems to happen regardless of batch size.  The issue has been witnessed with as few as a couple of pages up to the maximum amount the adf can hold but the finished pdf file is always the correct quantity of pages.  Never once has there been a misfeed in the ADF that I have witnessed and never is there an error message or problem at the printer end, just the finished file shows the malfunction.  I have tried to reproduce the issue using the ADF for a copy job.  Unless I am really lucky several hundred copy scans through the ADF do not produce solid white or black pages, only with the scan to pdf does this occur.

Any input would help.  Nothing in the network or settings has changed that we can figure out.  This is an issue that happens to over a dozen users (everyone doing scan to folder) working off of several different machines and Windows operating system versions.  The only common denominator is the server.  I can find no prior reference to this in the message boards and a search through firmware updates does not indicate anything either.

Thanks