Here's a list of bugs and glitches that I've encountered while building a base at Sanctuary Hills (don't know if these bugs apply to all settlements.)

1. Pip-boy glitch

When I'm exploring in the wasteland, my Pip-boy claims that there are only few beds, no food and no defences at my base but when I travel back to my base, the stats automatically fix themselves and when I leave, the stats go back to 0 again.

2. Defend Sanctuary Hills miscellaneous quest

Got a quest to defend my base so I went back there, defeated all Synths that attacked but the quest was still active and when I left, I got a message saying that the quest had failed so I went back to see what happened -> everyone had died and everything was broken to pieces. Tried to load a save -> no difference, same thing happened. Restarted the game -> no difference. Waiting at the base doesn't do anything, nothing happens and the quest remains uncompleted (though it instantly fails if I stay away too long.) Also Dogmeat attacked one of the settlers (maybe he was a Synth but no one else seemed to pay attention to him and no, Dogmeat wasn't travelling with me at the moment and no, I didn't shoot/hit him.)

3. Happiness bug

For some reason, happiness in my base goes down for no reason. All resources are green, there are defences, there's work for everyone, hell I even decorated the place to make it feel like home (maybe they all like to live in hunger, thirst and in an empty, boring, colorless world.) This bug might relate to the uncompleted quest that I explained at 2 (settlement being under attack all the time.)

4. Lazy Settlers bug

I assigned a few settlers to keep watch at the barricades but they seem to have lost interest in doing that since now, they are hanging out at my farming grounds, standing, refusing to move. The barricades still claim that someone has been assigned to those but no one is there. I tried to assign different settlers -> barricades guarded but those two still aren't moving.

5. Powering issues

Sometimes, lamps won't light up, even if they're right next to the generator/cable/power conduit.

A lot of issues for 1 SETTLEMENT don't you think? Especially number 2 and 3 are gamebreaking and need to be addressed asap.

Thank you for reading. Comment if you want me to add something or to fix my claims (and grammar.)