diff --git a/lib/fluent/plugin/in_tail.rb b/lib/fluent/plugin/in_tail.rb
index deea7c9498..cf12810953 100644
--- a/lib/fluent/plugin/in_tail.rb
+++ b/lib/fluent/plugin/in_tail.rb
@@ -498,7 +498,8 @@ def update_watcher(target_info, pe)
         pe_inode = pe.read_inode
         target_info_from_position_entry = TargetInfo.new(path, pe_inode)
         unless pe_inode == @pf[target_info_from_position_entry].read_inode
-          log.debug "Skip update_watcher because watcher has been already updated by other inotify event"
+          log.warn "Skip update_watcher because watcher has been already updated by other inotify event",
+                   path: path, inode: pe.read_inode, inode_in_pos_file: @pf[target_info_from_position_entry].read_inode
           return
         end
       end