Aside from some sorts of sap-tapping (such as of sugar maples for human consumption), most sap-oozing is in response to wounds or insect damage, as far as I've been able to find out via internet research. I'm not an expert on plant pests or plant diseases by any means, but as a plant ecologist, I do know it's not 'normal' for trees to ooze sap.
But, it's been interesting to observe the red admirals, commas, question marks, hornets, and other insects visiting the (obviously stressed) oak in the center of the planted area between the Caboose parking area and the Garden sign.
Take a look while the weather is still warm, if you're in the area. It's the oak at the highest point, closest to the irrigation faucet, directly across from the Cadet Life Garden.