Problem with sling - Crosstac Ambi Solid Gun Sling

Have a ar with a varmint barrel and light. Used the sling a couple times with no issues. The third time took the gun out of the tripod and went to sling it on my shoulder and the top spring clip let go. All three of us looked at it. I clipped it back on the gun and not 3 seconds later it Came-off again. The next day I looked at the spring clip and the hook barely was making contact with the stop.