Stray kittens are like that. I knew some strays that had their kittens. I would come by with food and for play time. Their mom was quite happy and joined in. This made the kittens trust people too much and… well, some people took them home when they were too damn young to be adopted. Knowing how most people are who spontaneously adopt strays they probably got tired of them really quick and abandoned them far away. It pains me to think of that