diff --git a/packages/core/modules/export/queryString.js b/packages/core/modules/export/queryString.js
index 71a18b96a..dc64008f1 100644
--- a/packages/core/modules/export/queryString.js
+++ b/packages/core/modules/export/queryString.js
@@ -54,7 +54,7 @@ const formatGroup = (item, config, meta, parentField = null) => {
 
   const isRuleGroup = (type === "rule_group");
   // TIP: don't cut group for mode == 'struct' and don't do aggr format (maybe later)
-  const groupField = isRuleGroup && mode == "array" ? properties.get("field") : null;
+  const groupField = isRuleGroup && mode === "array" ? properties.get("field") : null;
   const groupOperator = type === "rule_group" ? properties.get("operator") : null;
   const groupOperatorCardinality = groupOperator ? config.operators[groupOperator]?.cardinality ?? 1 : undefined;
   const canHaveEmptyChildren = isRuleGroup && mode === "array" && groupOperatorCardinality >= 1;
@@ -71,7 +71,7 @@ const formatGroup = (item, config, meta, parentField = null) => {
     conjunction = defaultConjunction(config);
   const conjunctionDefinition = config.conjunctions[conjunction];
 
-  const conjStr = list.size ? conjunctionDefinition.formatConj(list, conjunction, not, isForDisplay) : null;
+  const conjStr = list.size ? conjunctionDefinition.formatConj(list, conjunction, not, isForDisplay, groupField) : null;
   
   let ret;
   if (groupField) {
@@ -245,6 +245,9 @@ const formatRule = (item, config, meta, parentField = null, returnArgs = false)
   if (returnArgs) {
     return args;
   } else {
+    if (formattedValue === undefined)
+      return undefined;
+
     //format expr
     let ret = fn.call(config.ctx, ...args);
 
@@ -317,7 +320,7 @@ const formatField = (config, meta, field, parentField = null, cutParentField = t
     const fieldLabel2 = fieldDefinition.label2 || fieldFullLabel;
     const formatFieldFn = config.settings.formatField;
     const fieldName = formatFieldName(field, config, meta, cutParentField ? parentField : null, {useTableName: true});
-    ret = formatFieldFn(fieldName, fieldParts, fieldLabel2, fieldDefinition, config, isForDisplay);
+    ret = formatFieldFn(fieldName, fieldParts, fieldLabel2, fieldDefinition, config, isForDisplay, parentField);
   } else if(isDebugMode) {
     ret = "?";
   }
diff --git a/packages/core/modules/index.d.ts b/packages/core/modules/index.d.ts
index db094c3c6..2c45462c3 100644
--- a/packages/core/modules/index.d.ts
+++ b/packages/core/modules/index.d.ts
@@ -919,7 +919,7 @@ export type Widgets<C = Config> = TypedMap<Widget<C>>;
 // Conjunctions
 /////////////////
 
-type FormatConj = (children: ImmutableList<string>, conj: string, not: boolean, isForDisplay?: boolean) => string;
+type FormatConj = (children: ImmutableList<string>, conj: string, not: boolean, isForDisplay?: boolean, groupField?: string) => string;
 type SqlFormatConj = (children: ImmutableList<string>, conj: string, not: boolean) => string;
 type SpelFormatConj = (children: ImmutableList<string>, conj: string, not: boolean, omitBrackets?: boolean) => string;
 
@@ -1240,7 +1240,7 @@ type ChangeFieldStrategy = "default" | "keep" | "first" | "none";
 type FormatReverse = (q: string, op: string, reversedOp: string, operatorDefinition: Operator, revOperatorDefinition: Operator, isForDisplay: boolean) => string;
 type SqlFormatReverse = (q: string) => string;
 type SpelFormatReverse = (q: string) => string;
-type FormatField = (field: FieldPath, parts: Array<string>, label2: string, fieldDefinition: Field, config: Config, isForDisplay: boolean) => string;
+type FormatField = (field: FieldPath, parts: Array<string>, label2: string, fieldDefinition: Field, config: Config, isForDisplay: boolean, parentField?: string) => string;
 type FormatSpelField = (field: FieldPath, parentField: FieldPath | null, parts: Array<string>, partsExt: Array<SpelFieldMeta>, fieldDefinition: Field, config: Config) => string;
 type CanCompareFieldWithField = (leftField: FieldPath, leftFieldConfig: Field, rightField: FieldPath, rightFieldConfig: Field, op: string) => boolean;
 type FormatAggr = (whereStr: string, aggrField: FieldPath, operator: string, value: string | ImmutableList<string>, valueSrc: ValueSource, valueType: string, opDef: Operator, operatorOptions: OperatorOptionsI, isForDisplay: boolean, aggrFieldDef: Field) => string;