Some of you guys might have the pro eagle jack or just the extension on you HF jacks. Keep an eye on the welds. Had this happen to me a couple days ago. Heard a loud pop while I was under a truck but jack stands saved it from falling.
There was a lot of porosity in the material which indicates a low quality alloy mix in the aluminum. There was also little to no weld prep to the joint.
I ordered a new extension from kartek. The new version is made of steel, not aluminum but the weld still looks suspect. Not a lot of penetration but I can fix this one if it fails.