Additional info I received in an email 8.20.
FYI, as a follow-up and to make sure you have the latest information, the message from UDAP generated a brief discussion among several of our study team members. NAME REMOVED (NPS-Yellowstone NP) reminded us that recent research indicates that due to head pressure (as measured in a laboratory setting), the first 1-second blast of bear spray uses up about 40-45% of the product and propellant, with the amount of product and pressure of propellant decreasing rapidly with each additional 1-second of spraying. So by giving the can a "test blast", you would be using up your best blast of bear spray (as measured in amount of product and spray distance), and thus your best chance of stopping a bear.
Rather than a test spray, our recommendation would be to replace the bear spray canister altogether (and properly dispose of products with these lot numbers).