Time Machine is trying to backup
Did some research and found this: Time Machine Full Backup Issue.

Here is what it says on the site:


  Time Machine will always do a full backup in these circumstances:
  
  
  Backing-up from a new disk or partition (only that disk/partition gets a full backup).
  Backing-up to a new or erased disk or partition.
  After a full restore (not a "smart update") from a "clone" such as CarbonCopyCloner or SuperDuper.  This includes getting a new HD or
  erasing your current one, and using the clone to restore your data. 
  Effective with Lion 10.7.x, you may be able to prevent it via item #B6).
  After replacing or erasing your internal HD, and putting your data back “piecemeal.”  This includes dragging selected items or restoring
  selected items via the Time Machine “Star Wars” display.  Effective
  with Lion 10.7.x, you may be able to prevent it via item #B6).
  Going many days (at least 10, usually many more) without a backup, if a lot of changes have been made.