Hi Skipper. . . It is Skip again!!
Most people don't use probe thermometers for ribs. It is just too hard trying to find enough meat and deep enough meat to get good probe penetration. As Glued mentioned, your probe may be going through the meat or touching the bone or touching the rack or something like that. Regardless, I would suspect a faulty reading for some such reason.
You didn't mention if you are using the 3-2-1 method. If so, all you need to do is monitor the ribs and follow those guidelines. After three hours in the smoker and a couple in the foil, then a final hour on the rack again, you should be good to go.
If you are Smoking without foiling then monitor the pull back of the meat. You will eventually reach a point where the meat will begin to recede, or pull back from the ends of the bones. You are looking for between 1/4 to 1/2 inch. As you see this begin to happen, pick the ribs up in the middle with tongs. If they droop nicely, begin to crack or split and if they have the meat receding they are done or close to it. If still stiff, plop them back in for a while and check them again in another 30-45 minutes.
There are many on the forum with more experience than me. I am sure they will be along shortly. Meanwhile just relax and keep going following this, depending upon whether yo are using 3-2-1 or not. You can't hurt anything between now and when some more advice shows up.
Make sure you keep us posted on how this comes out.