This happens to me about once every few months. I still don't have a grasp on why it happens, but I'm familiar enough with it to have a system to recover. My wife is not so fortunate, and it tends to happen when she's home alone
I am proficient enough with it that I can recover the shot when it happens. When the burrs load up and your dose of beans is just swirling around in the throat, open the grind up while it's running
until it finally starts grinding again. You can hear the tone change when the pre-breaker section of the burrs start grabbing beans. The first couple times you do this the dose will be waisted as the grinder spews a dose of drip grind beans in your face very quickly. But once you recognize the sound change, you can quickly set the ring right back where it was and finish the dose.
I have had Duranium burrs from Duramill in my SJ for 4 years now, and when this happens, I usually open the burrs ~30-40° to get the "she's gonna blow!" change in tone, then I swing it back maybe a hair coarser than it was and generally I end up with a fairly decent cup from the grinds. Oddly, the shots always pull slower when this happens, not faster...
Anyway, after this happens I can usually go about my grinding business uninterrupted for another 6 to 9 weeks and then it randomly does it again. For what it's worth, I don't remember this ever happening when I used the hopper. But I got tired of throwing away 5g every single morning... I'm very interested to hear if anyone has a cause and solution for this issue...