A REPL cache with index auto-config, during State transfer is skipping index of data.
The order of events observed is:

CACHE_STARTING LIFECYCLE -> ST HAPPENS -> DATA WRITTEN -> CACHE STARTED LIFECYCLE

During data writes, the ProtobufValueWrapperIndexingInterceptor is activated by Hibernate Search and skips the indexing altogether since the ProtobufValueWrapperSearchWorkCreator is not used, and thus it cannot extract the descriptor from the entities. That search creator is only installed at cacheStarted phase.