Salesforce has recently made changes to the way bulk/batch calls are made.

This was previously updated in the Salesforce Spring '18 release notes.

Update : This article https://releasenotes.docs.salesforce.com/en-us/spring18/release-notes/rn_forcecom_flow_invocable_cruc.htm is no longer available now at Salesforce release notes.


Per our tests, this change does not have any impact on the way bulk updates are processed by the SFDC Connector and it will not add up to your API usage count.