I think it is a problem. First, there's no benefit, so why is the software letting it happen. Second, I don't think it's healthy for a battery to constantly add a trickle charge, whether from 99% to 100% or 79% to 80% (if you set the car the car for a max charge of 80%). I believe each charging cycle can cause degradation, so its harming the battery with no benefit. Third, it can be dangerous. It makes me uncomfortable to know that my car can be constantly drawing power. The possibility of something going wrong increases if a connection is kept open when it isn't necessary, or repeatedly reopens for an unneeded charge.
And imagine this happening if you leave your car plugged in for days at an airport or train station. Every day the car will initiate a new charge every time it drops down 1%. That's crazy.