Synopsis of the problem:

Albert Einstein, On the Electrodynamics of Moving Bodies, 1905: "From this there ensues the following peculiar consequence. If at the points A and B of K there are stationary clocks which, viewed in the stationary system, are synchronous; and if the clock at A is moved with the velocity v along the line AB to B, then on its arrival at B the two clocks no longer synchronize, but the clock moved from A to B lags behind the other which has remained at B..." http://www.fourmilab.ch/etexts/einstein/specrel/www/

Einstein's conclusion: "the clock moved from A to B lags behind the other which has remained at B"

Einstein's conclusion is non sequitur - it does not follow from Einstein's 1905 postulates. The following two conclusions do follow from the postulates but involve no meaningful prediction:

Conclusion A: The clock moved from A to B lags behind the other which has remained at B, as judged from the stationary system.

Conclusion B: The clock which has remained at B lags behind the clock moved from A to B, as judged from the moving system.