diff --git a/src/main/java/org/prebid/server/auction/AmpRequestFactory.java b/src/main/java/org/prebid/server/auction/AmpRequestFactory.java
index 4b7a3130c41..ee60140194e 100644
--- a/src/main/java/org/prebid/server/auction/AmpRequestFactory.java
+++ b/src/main/java/org/prebid/server/auction/AmpRequestFactory.java
@@ -636,7 +636,7 @@ private ExtRequestTargeting createTargetingWithDefaults(ExtRequestPrebid prebid)
 
         final Boolean includeFormat = !isTargetingNull ? targeting.getIncludeformat() : null;
 
-        return ExtRequestTargeting.builder()
+        return (isTargetingNull ? ExtRequestTargeting.builder() : targeting.toBuilder())
                 .pricegranularity(outgoingPriceGranularityNode)
                 .mediatypepricegranularity(mediaTypePriceGranularity)
                 .includewinners(includeWinners)
diff --git a/src/test/java/org/prebid/server/auction/AmpRequestFactoryTest.java b/src/test/java/org/prebid/server/auction/AmpRequestFactoryTest.java
index 864a85ce91b..dc4e75455ca 100644
--- a/src/test/java/org/prebid/server/auction/AmpRequestFactoryTest.java
+++ b/src/test/java/org/prebid/server/auction/AmpRequestFactoryTest.java
@@ -26,6 +26,7 @@
 import org.prebid.server.auction.model.AuctionContext;
 import org.prebid.server.exception.InvalidRequestException;
 import org.prebid.server.metric.MetricName;
+import org.prebid.server.proto.openrtb.ext.ExtIncludeBrandCategory;
 import org.prebid.server.proto.openrtb.ext.request.ExtGranularityRange;
 import org.prebid.server.proto.openrtb.ext.request.ExtPriceGranularity;
 import org.prebid.server.proto.openrtb.ext.request.ExtRegs;
@@ -398,6 +399,29 @@ public void shouldReturnBidRequestWithDefaultPriceGranularityIfStoredBidRequestE
                                 ExtGranularityRange.of(BigDecimal.valueOf(20), BigDecimal.valueOf(0.1)))))));
     }
 
+    @Test
+    public void shouldReturnBidRequestWithNotChangedExtRequestPrebidTargetingFields() {
+        // given
+        givenBidRequest(
+                builder -> builder
+                        .ext(givenRequestExt(ExtRequestTargeting.builder()
+                                .includebrandcategory(ExtIncludeBrandCategory.of(1, "publisher", true))
+                                .truncateattrchars(10)
+                                .build())),
+                Imp.builder().build());
+
+        // when
+        final BidRequest request = factory.fromRequest(routingContext, 0L).result().getBidRequest();
+
+        // then
+        assertThat(singletonList(request))
+                .extracting(BidRequest::getExt).isNotNull()
+                .extracting(ExtRequest::getPrebid)
+                .extracting(ExtRequestPrebid::getTargeting)
+                .extracting(ExtRequestTargeting::getIncludebrandcategory, ExtRequestTargeting::getTruncateattrchars)
+                .containsOnly(tuple(ExtIncludeBrandCategory.of(1, "publisher", true), 10));
+    }
+
     private Answer<Object> answerWithFirstArgument() {
         return invocationOnMock -> invocationOnMock.getArguments()[0];
     }