diff --git a/csaf_2.1/prose/edit/src/tests-02-optional.md b/csaf_2.1/prose/edit/src/tests-02-optional.md
index 0d6efe7a6..30c6bf717 100644
--- a/csaf_2.1/prose/edit/src/tests-02-optional.md
+++ b/csaf_2.1/prose/edit/src/tests-02-optional.md
@@ -648,7 +648,8 @@ The relevant path for this test is:
 
 ### Same Timestamps in Revision History
 
-It MUST be tested that the timestamps of all items in the revision history are pairwise disjoint, when converted to UTC.
+It MUST be tested that the timestamps of all items in the revision history are pairwise disjoint.
+To ensure the correct result, the timestamps SHALL be converted to UTC before checking their uniqueness.
 
 The relevant path for this test is: