Was this “evolving” failure of the shark bite a result of USING the shutoff valve?

I ask because, in my home, there was an old,non-functional, water softener. I removed it, made a “loop” with the in and out pipes and sharkbited them. This was, at least, 5 yrs ago and it’s still holding strong.

Maybe the stresses of operating the shutoff valve caused the failure? Just wondering, not criticizing in any way.