This wasn't happening before, but the other nite I put on all my fancy charismatic clothes, got high on chems and beer aND very charismatically convinced an additional 10 dwellers to leave hangman's alley and join the cause at sanctuary. Bringing my total population to 33.
Since then, however, I've noticed at sanctuary and star light (population 17) that if I assign any one to anything then every one in my entire settlement stops working and my food drops to 0 and my defenses drop to only automated defenses. It happened at sanctuary as well. I tried to put one of my new settlers on farming and EVERY BODY quit! I have plenty of food, beds, water, etc. Happiness of 85+.... I don't get it!! I had to reload my game to before everyone stopped working but now I'm left with 10 unemployed settlers at sanctuary. Am I missing something? Am I doing something wrong? Help?

Maybe I should add that I'm playing on ps4

There is a limit on how many people can be in a given settlement. With zero effort on my part I get up to 22. More than that would require me to actually read a guide regarding the necessary tricks to get it higher. Now there are people with upwards of 50 settlers but that is a fairly major undertaking.

It seems people over whatever your current limit causes the settlement to go poof.

So I should start moving settlers out until I find that sweet spot.. unless it's too late..