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
Not the problem.
Legionella grows from 69F to 122F, and grows better near the upper end of this range. You have to get above 140F and maintain for some time to actually kill it.
Since 140F also quickly causes scalding, it isn't used much, for obvious reasons.
I wonder if they have inadequate chlorine residual?
Well, that could very well be. Come to think of it, quite a few restaurants that I have been to, don’t even seem to have hot water in the restrooms, lately.