bug report on update-index --assume-unchanged

Hi,

I add 2 files that I want ignore on commits git update-index --assume-unchanged configurations/local.defs git update-index --assume-unchanged processor/default.defs

git diff -a is clean git diff . is clean git commit -a

nothing added to commit

but 

git commit . # Changes to be committed: # modified: configurations/local.defs # modified: processor/default.defs

this is a bug .

thanks