We recently had a client that was using IE (I know, ish) to view the web client.  They were seeing a picklist with entries that were not in the system.  It was like the picklists had been cached.  In fact, I think this to be the case.  In order to speed up picklist performance the web client is caching picklist somehow for the browser.  The problem arose when I tried to delete the browser cache to clean up the picklist, the choices still persisted. 

 The solution I eventually found, was to go into Administration…Picklists and add a new picklist item to any picklist.  I then immediately removed the item.  bingo!  The browser’s picklist cache was refreshed and the correct items were showing.

This was something I have not seen before.  It was on the v8.1.5 client.  So if you ever run into this behavior, try this fix.  It may save you some time.