I’ve had this ongoing problem for years and finally figured my own fix… poke one small hole with toothpick into kcup prior to using. That solved most of my volcanic problems.
Irony, bought new machine last month and now the machine pokes FIVE holes in top vs one. Sad note, I get about 20 grounds in the following two cups brewed… which is not fun in my chai tea. Now I run two cups of water through after my husband does his coffee. About to give up on Keurig and k cups forever and I’ve purchased 6 + machines over the last 8 years ( home, office, cabin, …)