Version:            (using KDE 4.2.2)
OS:                Linux
Installed from:    Ubuntu Packages

If static word wrap is turned on, and I insert a sentence before already existing text, the word wrap skips a word.  It's hard to describe, here's an example.

Start a text file with:

Hello I am a sentence.

Then place the cursor at the beginning of the document, before "hello" and type: "Hello, I am inserting a sentence to test word wrapping, it will produce odd results"

This produces the following text:

Hello, I am inserting a sentence to test word wrapping, it will produce odd\n
Helloresults I am a sentence.

(Where \n is the newline.)

Notice that although you were inserting before "Hello", the word wrapping moved the cursor after "Hello" and inserted the word "results".