How good is the cable tester? Is it a decent model? If it is a cheap model it may be it isn't recognising issues with the cables. The fact some work and some don't suggests there is something wrong with the termination.
Are you terminating at sockets? If so are they screw terminals or punch down IDCs? I had problems with some sockets I had bought as no matter how well they were punched down they didn't work - swapping out the socket fixed the issue.
I have to assume the same kit is being used to test all the cables - hopefully plugging in to a switch at one end and a laptop at the other. If we can rule out differences in kit then it is only the cable and sockets being tested.
For testing I would use the same switch port, the same patch cables, the same network drop lead and the same laptop. That leaves the only difference being the actual structured cabling.