diff --git a/hapi-fhir-base/src/main/java/ca/uhn/fhir/model/primitive/BaseDateTimeDt.java b/hapi-fhir-base/src/main/java/ca/uhn/fhir/model/primitive/BaseDateTimeDt.java
index f751de1be17..c6c0b8d0afa 100644
--- a/hapi-fhir-base/src/main/java/ca/uhn/fhir/model/primitive/BaseDateTimeDt.java
+++ b/hapi-fhir-base/src/main/java/ca/uhn/fhir/model/primitive/BaseDateTimeDt.java
@@ -586,8 +586,7 @@ public abstract class BaseDateTimeDt extends BasePrimitive<Date> {
 	}
 
 	private TimeZone getTimeZone(String offset) {
-		return timezoneCache.computeIfAbsent(offset, (offsetLocal) ->
-			TimeZone.getTimeZone("GMT" + offsetLocal));
+		return timezoneCache.computeIfAbsent(offset, TimeZone::getTimeZone);
 	}
 
 	public BaseDateTimeDt setTimeZone(TimeZone theTimeZone) {