I have a Renishaw Wireless probe on my HAAS TM-1P.
The instructions in the book and on the screen tell you to get within .4 of the part with the probe. It you are at .5 it may be alarming out due to not touching something within the .4 requirement. This has happened to me on occasion.
If you have the wireless probe you may also want to check the batteries. It will act crazy when the batteries get low.
Just a couple of things you might want to look at.