diff --git a/app/models/changeset.rb b/app/models/changeset.rb
index 4256f0589..b5ef7b298 100644
--- a/app/models/changeset.rb
+++ b/app/models/changeset.rb
@@ -126,11 +126,11 @@ class Changeset < ActiveRecord::Base
 
     referenced_issues = []
 
-    comments.scan(/([\s\(\[,-]|^)((#{kw_regexp})[\s:]+)?(#\d+(\s+@#{TIMELOG_RE})?([\s,;&]+#\d+(\s+@#{TIMELOG_RE})?)*)(?=[[:punct:]]|\s|<|$)/i) do |match|
+    comments.scan(/([\s\(\[,-]|^)((#{kw_regexp})[\s:]+)?(OS#\d+(\s+@#{TIMELOG_RE})?([\s,;&]+#\d+(\s+@#{TIMELOG_RE})?)*)(?=[[:punct:]]|\s|<|$)/i) do |match|
       action, refs = match[2].to_s.downcase, match[3]
       next unless action.present? || ref_keywords_any
 
-      refs.scan(/#(\d+)(\s+@#{TIMELOG_RE})?/).each do |m|
+      refs.scan(/OS#(\d+)(\s+@#{TIMELOG_RE})?/).each do |m|
         issue, hours = find_referenced_issue_by_id(m[0].to_i), m[2]
         if issue && !issue_linked_to_same_commit?(issue)
           referenced_issues << issue