I assume we have eliminated coatings and sauces on the beef or pork. BBQ flavoured anything is a sure sign of trouble. I also assume that the beef or pork are not processed like beefburgers or sausages. I have found that certain brands of beef slices are heavily laced with Maltodextrin or similar sugar product., as are faggots in gravy. Sausages can also have added flavourings
If simple butchers type meat is spiking, then I too have a conundrum to solve. I do parallel testing with two meters on the same drop of blood. On many meals they track reasonably within the 15% accuracy band, but they can disagree severely after a meat dish. One meter records what I would consider reasonable results for a protein heavy meal, but the other one jumps up a couple of points higher, and repeats the reading on retest. So one meter seems to be sensitive to something in my blood that the other does not see. It may be the lipid load / chylomicrons, or sensitive to certain fatty acids but its repeatable.
I recently changed the meter that reads high for a different one. But the new one uses the same strip technology and it too is doing the same thing. So it seems to be the enzyme chemical reaction is being interferred with, not a faulty meter. These meters are both SD meters and made in China