It appears that this happened because your last batch in your epoch has 1108 (pictures, ect) in it where your model is expecting 1120.
This is what ’ markdaoust’ was trying to explain, but I think it most often happens at your last batch of your epoch, since if you don’t divide out the right number of item it will not naturally be the 1120. take  items //batch_size to only get an integer.