The problem with these MK3 and PPC boards is that there are no BGA 68060 sockets, they simply do not exist.
Phase 5 (and DCE) made their own by taking a regular sockets and sawing (and grinding) the pins off. This works, obviously but the connections aren't as strong as real BGA's using balls of lead. Because the 68060 gets quite hot (68040 even more) these pins tend to work loose.