Profession morale expectations do not change

their morale stays at that of their highest tier mastered job.
 

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eg; A dupe with mastery in research assistant can continue to use the super computer when switched to another job, and they keep the +2 learning of course.
A dupe with mastery in supply keeps the +400kg carry bonus and the +2 Str when shifted to another job.
A dupe with mastery in both supply jobs has +4 str and +1200kg carry bonus since the buffs stack, and keeps that when shifted to another job.

All the buffs of a job are kept once it's mastered.

As are all of the expectations

If a job has been mastered, the dupe will keep the morale expectations for that job no matter what.