This issue was identified as a regression and will be fixed with defect Invalid attachments field names gathered by the Change Event cause attachment deletion during incoming sync (204959)

Issue: we found that the latest version of the JazzInterop package introduces a regression that could cause the Attachments field name gathered by the Change Event to be invalid, which in turn causes attachments to be deleted.

This regression was likely introduced during implementation of CQ Synchronizer not handling multiple attachment fields even though sync rule is not syncing them (158915)

Workaround: revert the JazzInterop package to a version less than 1.10
https://www-304.ibm.com/support/docview.wss?uid=swg21503716
or manually apply the following modification ot the CQ schema:
1. Enable package editing
At a dos command prompt, type the following, substituting the values as appropriate such as schema-repo-name, username, password, and username.
packageutil enablepackageediting -dbset schema-repo-name username password -enable username

2. In CQ designer, checkout the schema and locate this method "addAttachmentsRecords" (you can use "Find in Hook" with the CQ windows designer for this)

3. In the for loop, find this line
$field_value .= "<field name=\"$attachfield->GetFieldName()\"";

and replace it with
$field_value .= "<field name=\"Attachments\"";

4. Checkin the schema and upgrade the user database.