Positive pressure HEPA mask not working fully for woodworking

I have a 3M Versaflo TR-300 and am using a 3M HE Filter TR-3712N filter on it. It mostly seems to work, but at times, like when using the tablesaw, I can smell sawdust. My sinuses get irritated easily from woodworking, so I'm trying to figure out if there's anything I should be checking or doing differently to avoid that. Even when wearing my mask the whole time in the shop, I'm still getting a reaction to the sawdust.

I checked the air pressure with the device that comes with the versaflo and it was significantly above the recommended pressure. I only use my filter once a week or so and change it maybe every 6 months. It doesn't look dirty, but I suppose that could explain the issue.

Anyone else have any suggestions or resources I can look into for how to make this system dust-secure so I can do woodworking without pissing off my sinuses for the next few days?