In a test environment, I noticed that a node with revisions that should be pruned was not being processed. It appears the $last_nid gets stuck (not reset to 0) if all nodes with an entity_id greater than $last_nid do not have any candidate revisions.
If for example, you have 3 nodes (nid 1, 2, 3), set the following:
\Drupal::state()->set('cm_revision_delete.last_nid', 2);
Make sure nid 3 doesn't have any candidate revisions. The latest_nid will not be reset back to 0 in order to start processing at the beginning of the list.
Check if cm_revision_delete_get_node_candidate() returns anything, else set latest_nid back to zero.
Fixed
1.1
Code
Automatically closed - issue fixed for 2 weeks with no activity.