Reloading Press Powder Dispenser Pressure

Yesterday my Lee powder dispenser to my reloading press popped off gunpowder everywhere

I had removed the top part of the container off and placed it back on, there is a "on" / "off" mechanism in the product design. I’m fairly confident the reservoir was tightly secured.

Is pressure able to be built in a plastic container? Has this happened to anyone else? Are there best practices to prevent gunpowder spills.