Low water level in the bowl of the toilet after flushing
If you have a plugged sewer vent or a plug in a line to the vent, then water can get sucked out of the trap in the toilet. I believe that this is the reason low water in the bowl occasionally occurs in plumbing that has no permanent fault.

I just poured a bucket of water into a properly operating toilet and the water drains down to a very low level in the toilet. So this is normal. The water supply system in the tank is supposed to continue a gentle flow into the bowl after the flush is finished to raise the level in the bowl to the height that the design of the toilet trap allows. In your malfunctioning toilet the water supply may not be directing the flow through the small flexible hose into the overflow tube. With the tank lid off compare a flush in the basement toilet to a flush in one of the properly operating toilets.