I'm sorry if there is a thread for this already, please feel free to direct me to it. I'm having a pretty big issue with Sanctuary. It's fairly big now (19 people) and I have a lot of resources there. Lately though and with increasing frequency, when I leave and randomly look at the data-settlements part in the pip-boy, there will be an alert for water and show it at 0. I normally have 50+ water. The happiness will have dropped severely (sometimes by 20), but when I fast travel back, the correct number for water is displayed and the alert is gone. The happiness however stays at it's new low. I sometimes get erroneous alerts for other settlements as well and go through the same procedure of simply traveling there for the problem to go away.

Are there any fixes for this?

No fixes from what I've found, but yeah it's pretty common and there are a few threads. 3 of my 4 settlements all show alerts as well when I'm away from them and look in the pipboy. Every time I run to any of them (I don't use fast travel at all) everything is fine and all levels, including happiness, are what they should be.

I've made the thread some time ago regarding this bug, and there's another user who made a thread about this same issue.

There's a workaround to this:

Don't fast travel when you're in Sanctuary. Walk outside of Sanctuary's border and then you can use fast travel (I usually walk to Red Rocket, but another user says you don't need to walk that far).