Can I weld my cam bolts?

The only thing you should ever have to do to the UCA camber bolts is torque them to spec.

If that doesn’t hold them, you’ve got something else going on. I even grease the UCA bolts and the backside of the eccentric washers on my cars so they’re easy to adjust when I set the alignment. Never had them move after they’ve been torqued.

There were some batches of cam bolts that didn’t have the flat cut far enough down the bolts, so the eccentric washer would bottom out before any clamp force was applied to keep the bolt from moving. But it sounds like you have the same problem with the stock bolts, so something else is probably going on. My bet would be on something other than the cam bolts moving, but that’s just my guess. More likely you’ve got something broken somewhere, or the LCA pivot pins were tightened with the car in the air and the rubber LCA bushings tore when the car sat down to ride height.