You can call your county extension for help with canning questions.
Here is what I found on the web:
Sometimes after processing, some of the water or canning liquid in the jar is lost and doesn't cover the product. Lost water is most common when pressure canning, especially with starchy foods. Typical causes and solutions are:
Packing the food too tightly or loosely in the jar.
Starchy foods, such as corn, peas or lima beans, absorbed all the liquid. Use more liquid with these starchy vegetables.
Air naturally entrained within the fruit or vegetable that wasn't released (generally this happens more with raw pack than hot pack)
The jars filled too full (too much vegetable/fruit compared to the amount of liquid).
In pressure canning: Fluctuating pressure in the pressure canner. Let pressure return to zero gradually, avoiding the sudden release of pressure through the vent. Do not hasten the cooling with cold water.
In water bath canning: The jars are not totally covered with boiling water during the boiling water bath processing.
The food was not heated prior to filling (Raw pack method) -
All air bubbles were not removed prior to sealing the lids and rings on the jars.
As long as the jars remained sealed, they'll be ok, but they should be checked more frequently and used up first!
http://www.pickyourown.org/canning-p...-of-liquid.php