Recently it come to my attention that using two different lead-free solder alloys in one process should not take place.
Example: populated PCB is flown on wave solderer with alloy X and then (if required) alloy Y used to rework any nonconforming joints. Is this practice allowed? What kind of electrical/mechanical downsides can be expected from reliability of this joint in long-term situation? Unit is exposed to vibrations and shock in it's life.
Thanks for answers, Seb