diff --git a/CHANGELOG.md b/CHANGELOG.md
index b77888084..7b2dcfc34 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Fixes
 
+- Bugfix in `Service11TelecommandScheduling` which allowed commands
+  time tagged in the past to be inserted.
+  PR: https://egit.irs.uni-stuttgart.de/fsfw/fsfw/pulls/738
 - `CService200ModeManagement`: Various bugfixes which lead to now execution complete being generated
   on mode announcements, duplicate mode reply generated on announce commands, and the mode read
   subservice not working properly.
diff --git a/src/fsfw/pus/Service11TelecommandScheduling.tpp b/src/fsfw/pus/Service11TelecommandScheduling.tpp
index 540f6c689..090d0fd62 100644
--- a/src/fsfw/pus/Service11TelecommandScheduling.tpp
+++ b/src/fsfw/pus/Service11TelecommandScheduling.tpp
@@ -160,7 +160,7 @@ inline ReturnValue_t Service11TelecommandScheduling<MAX_NUM_TCS>::doInsertActivi
   // (See requirement for Time margin)
   timeval tNow = {};
   Clock::getClock_timeval(&tNow);
-  if (timestamp - tNow.tv_sec <= RELEASE_TIME_MARGIN_SECONDS) {
+  if (timestamp < tNow.tv_sec + RELEASE_TIME_MARGIN_SECONDS) {
 #if FSFW_CPP_OSTREAM_ENABLED == 1
     sif::warning << "Service11TelecommandScheduling::doInsertActivity: Release time too close to "
                     "current time"