It's possible that the extract had a very high level of unfermentable sugars, 33% attenuation is ridiculous, though. Both of the yeasts you've pitched should do double that. Post the recipes and the brand name of the DME.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk