Contacts have an existing X500 addresses. Is there a way for the merge to preserve this x500 address?
When the merge/provision process occurs, an x500 address is generated by Notes Migrator for Exchange. This will overwrite any existing address. This is a default behaviour.
To have the merge/provision process append the address as an additional x500 address, add the following to the Global default Settings:
[ActiveDirectory]
MergeX500=1