diff --git a/projects/igniteui-angular/src/lib/grids/filtering/excel-style/excel-style-filtering.component.ts b/projects/igniteui-angular/src/lib/grids/filtering/excel-style/excel-style-filtering.component.ts
index f858fb12784..408fc8a8199 100644
--- a/projects/igniteui-angular/src/lib/grids/filtering/excel-style/excel-style-filtering.component.ts
+++ b/projects/igniteui-angular/src/lib/grids/filtering/excel-style/excel-style-filtering.component.ts
@@ -510,7 +510,8 @@ export class IgxGridExcelStyleFilteringComponent extends BaseFilteringComponent
         this.filterValues = this.generateFilterValues();
         this.generateListData();
         this.expressionsList.forEach(expr => {
-            if (this.column.dataType === GridColumnDataType.String && this.column.filteringIgnoreCase && expr.expression.searchVal) {
+            if (this.column.dataType === GridColumnDataType.String && this.column.filteringIgnoreCase
+                && expr.expression.searchVal && expr.expression.searchVal instanceof Set) {
                 this.modifyExpression(expr);
             }
         });