This Bible contradiction is from the Skeptic's Annotated Bible.
John 19:29-30 View context
Now there was set a vessel full of vinegar: and they filled a spunge with vinegar, and put [it] upon hyssop, and put [it] to his mouth.
When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost.
Mark 15:23 View context
And they gave him to drink wine mingled with myrrh: but he received [it] not.