And what does that have to do with construction water treatment by a specific contractor?

I too can dump contaminated water just doing renovations on my home by leaving it out or not following proper procedures for disposing of it.

There isn't a special AI related cause to it. It's a relatively rare bacteria that primarily impacts immunosuppressed patients when it shows up (which is rare) and there's only four known fatalities, and they mostly picked it up in hospitals while being treated for other things.

https://www.sciencedirect.com/science/article/pii/S1201971226000780 https://pmc.ncbi.nlm.nih.gov/articles/PMC5684090/

The contamination from the construction happened while they were doing flush and fill on the pipes at the facility, just like what would happen with any new building that contains plumbing. It can easily be cleaned with standard options like bleach if it's known to be an issue.