diff --git a/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/factory/data/OverwrittenData.java b/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/factory/data/OverwrittenData.java
index 9354d638c..f3ce7e530 100644
--- a/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/factory/data/OverwrittenData.java
+++ b/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/factory/data/OverwrittenData.java
@@ -135,7 +135,7 @@ public PendingImportObject<BrAPIObservation> constructPendingObservation() {
             original = observation.getValue();
         }
 
-        if (!isTimestampMatched() && timestamp != null) {
+        if (!isTimestampMatched() && StringUtils.isNotBlank(timestamp)) {
             // Update the timestamp
             DateTimeFormatter formatter = DateTimeFormatter.ISO_INSTANT;
             String formattedTimeStampValue = formatter.format(observationService.parseDateTime(timestamp));
diff --git a/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/middleware/process/ImportTableProcess.java b/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/middleware/process/ImportTableProcess.java
index 4a2846fcd..f2e74982e 100644
--- a/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/middleware/process/ImportTableProcess.java
+++ b/src/main/java/org/breedinginsight/brapps/importer/services/processors/experiment/appendoverwrite/middleware/process/ImportTableProcess.java
@@ -398,11 +398,8 @@ private boolean isChanged(String cellData, BrAPIObservation observation, String
         if (!cellData.isBlank() && !cellData.equals(observation.getValue())){
             return true;
         }
-        // Only check timestamp if the TS:<trait> column was present in the uploaded file.
-        if (timestampColumnPresent) {
-            if (StringUtils.isBlank(newTimestamp)) {
-                return (observation.getObservationTimeStamp()!=null);
-            }
+        // Only check timestamp if the TS:<trait> column was present in the uploaded file and there's a valid timestamp.
+        if (timestampColumnPresent && !StringUtils.isBlank(newTimestamp)) {
             return !observationService.parseDateTime(newTimestamp).equals(observation.getObservationTimeStamp());
         }
         return false;