As to Release notes of ZCS, and as I understand it, spam/ham training is enabled only on first installed MTA server. In case of multiple MTA server deployment:

1. If by default spam/ham training is enabled on one MTA, are there any procedures to sync these terms to other MTA servers?

Due to this, each MTA server has its own SA/AV engine, and has to get trained rules for this. If first MTA (where spam/ham is configured by default) gets such rules from users' Junk boxes, it deletes afterward such mails. And other servers are not available for these latest rules. Am I correct?