I've been losing mats more and more, sometimes on expensive synths due to this feature. I know it's to prevent people from cheating by disconnecting if it looks like they'll fail the craft. Therefore, save the synth data and resume the in-progress craft when you log back in so 1) you don't lose mats, 2) you prevent cheating. Simple solution, might require a bit more data being saved/transferred to the server but huge QoL improvement for all you big crafters out there.