Maybe they. use too little water. They always seems to turn off too soon You’re supposed to wash for a certain amount of time. It would be nice to know why.
If I remember from my limited microbiology legionella is heat sensitive. my experience with these types of faucets in airports etc. leads me to think that the water doesn’t get hot enough to kill the bacteria.... the water from these things always seems tepid too me.
Just a guess