There're some retention of the Lagom Mini, what can I do?

One of the things we will recommend (or to confirm first) is to let the grinder run for a bit longer (than what you're currently doing) until no coffee is being dispensed. Due to the low RPM (by intention/design as it appeared to give better result than high RPM), the evacuation of coffee ground can be a little slower.

Even after the coffee beans are completely ground, we will generally allow the grinder to keep going for about 10-15s until you no longer see any coffee grind being dispensed.

With staticky coffee or in a dry environment where static electricity can be a more severe issue, palm tapping on top of the funnel (after removing the lid) can also help create some airflow to evacuate the grind a bit more efficiently.