I wish that was the explanation! I’ve done some more reading and I think I have changed the pop-off pressure. I cleaned the carburetor recently and installed a new carb kit. I am thinking that the pop-off has changed due to the new diaphragm, check valve, fulcrum, and spring I installed. Time to learn how to tune the pop-off pressure.
You’re probably right about why it changed, but you’ve stumbled on the correct settings. A properly tuned Leopard will be have a tan flex and it shouldn’t be wet or oily. You were likely very rich before.