I see what you did. You have it moving the cutter to X0.0Z0.0. That is not what the G28 command really does and there is no value in that. It would just cause a crash.
The G28 command moves the cutter to machine zero (while going through the intermediate position). As an example G28U0W0 moves the cutter directly to the machine zero.
Please see my example above and note that I edited it because I screwed it up the first time around.
Dave