You are migrating Account with Contact details but the Phone Number and Mobile Number are not getting updated
Reproducing the Issue
1. Go to Business Configuration work center.
2. Select Implementation Projects view or Overview.
3. Search and Open the migration activity Migration of Customers.
4. Execute Migration for the respective Migration File.
The incoming message from ERP for a particular Account will not have any information for that specific Contact and hence the relationship breaks and that results in deletion of Mobile Number and Phone Number
If you only want to maintain the relationship of Accounts with Contacts in Cloud for Customer not in ERP then you need to set constant false for contactpersonlistcompletetransmissionindicator in ERP.
Element path: /ns0:BusinessPartnerERPBulkReplicateRequest/BusinessPartnerERPReplicateRequestMessage/BusinessPartner/@contactPersonListCompleteTransmissionIndicator
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