In certain situations, the Save & Merge button may not be available on the Resolve Conflicts page.
Working as intended.
The Save & Merge button showing up depends on whether or not the associated table is on the "merge record deny list" or not. The following tables are on the deny list:
This behavior is by design and cannot be modified. If you are resolving conflicts on the aforementioned tables, the Save & Merge button will not be shown. This is due to the fact that records from these tables have payloads which contain multiple records in one file, and this format is not supported when merging.