Even kiln dried wood of some species can occasionally ooze sap. When wood dries, concentrations of sap will crystallize. Changes in humidity and temperature (it is middle of summer and I suspect your shop does not have AC) can make pockets of sap a bit viscous. I have seen this in purpleheart myself.
I suspect there are some heavy veiny looking grains where you are noticing this sap coming from. A tree, while growing, can attempt to self heal flaws/cracks in its tissues by concentrating sap in the areas. This may be the case with your wood.
