DIAGNOSIS The reusable mesh filter basket has clogged with coffee oils, severely restricting water flow over the grounds. Water takes the path of least resistance and channels around them.
FIX Deep clean the filter basket immediately. Soak it in a solution of 1 part white vinegar to 2 parts hot water for 30 minutes. Scrub it vigorously with a soft brush (an old toothbrush is perfect) to dislodge the invisible oil film. Rinse thoroughly. For maintenance, do this every 2-3 weeks.
IF THAT DIDN'T WORK The spray head (the part that drips water) might be partially clogged with mineral scale, causing uneven saturation. Descale the entire machine: run a cycle with equal parts white vinegar and water, then run 2-3 cycles with clean water to rinse.
HEADS UP Never use soap on the reusable mesh filter—it will lodge in the mesh and ruin the taste. The vinegar soak and physical scrubbing is the only effective method.