For sure too much air. It could be entering from someplace not suspected. Loose vents etc. Can you use the Minion Method in a UDS?
Weber WSM, Weber GA, Weber Spirit S-320
Charbroil Oilless Turkey Fryer
Wife LuzziAnn 1956 model.
Maverick ET-732, Superfast LSU Purple Thermapen & ThermaPop, Party Q