Yes, this happened to me and my younger brother.
My father had taught me to retract my foreskin for cleaning in the bath, at an early age. I can certainly remember being able to retract at the age of 4, fully and painlessly. In fact I quite enjoyed the sensation of the skin sliding back over my sensitive glans, so I continued to retract it regularly during my early childhood, although I usually peed with the foreskin in its normal forward position.
Around the age of 11 or 12 my foreskin tightened over a period of a few weeks, or maybe months, until I could not pull it back at all. A tight collar of inflexible skin had formed around the opening, and even using extreme force to the point of pain, the opening would not stretch wider than about 5 or 6 mm, so only the slit in my glans was visible. Although I was very upset that I could no longer uncover my knob, I was too embarrassed to tell my parents (or anybody else), and hoped it would only be a temporary tightness. It turned out to be permanent.
Not much later, my parents discovered that my brother, then aged 6, could no longer pull back his foreskin. His had also been easily retractable previously, as I had seen for myself. He was taken to the doctor, who of course recommended circumcision, and he went into hospital for the operation shortly afterwards. I remember my father asking me if my foreskin was still OK, and as the prospect of circumcision terrified me, I lied to him and thankfully he didn't ask me to prove it.
Later in my teens when I began to realise that my tightness was permanent, I began to make attempts at stretching my foreskin. These would would be painful but unsuccessful, and I was never able to uncover more than the very tip of my glans. Sometimes the skin would split, and after it healed the skin was tighter than ever.
I eventually decided to get circumcised when I was 31.
As to why it happened, I think the most likely explanation is a condition called lichen sclerosis, which causes a thickening of the skin, and is often a cause of phimosis. Alternatively I may have damaged the skin with playing too aggressively with my foreskin, the scar tissue which then formed causing the tightness.