That's a bit of a bug, sort of. What you are seeing are 4 or more decimal places and there isn't enough room to display them properly, so it looks to be in the thousands. Your data is good though as you can see if you download the CSV for the yearly graph. It will get fixed eventually one way or another. You can see the same on the trend spotting graph for one of my stations:
https://radmon.org/index.php?option=com_content&view=article&id=30&station=radspod_one
