diff --git a/src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/Query/NorthwindAggregateOperatorsQueryFbTest.cs b/src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/Query/NorthwindAggregateOperatorsQueryFbTest.cs
index 0822ac872..778d544bf 100644
--- a/src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/Query/NorthwindAggregateOperatorsQueryFbTest.cs
+++ b/src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/Query/NorthwindAggregateOperatorsQueryFbTest.cs
@@ -91,4 +91,11 @@ public override Task Sum_with_division_on_decimal(bool async)
 	{
 		return base.Sum_with_division_on_decimal(async);
 	}
+
+	[Theory(Skip = "Different math on Firebird.")]
+	[MemberData(nameof(IsAsyncData))]
+	public override Task Contains_inside_Average_without_GroupBy(bool async)
+	{
+		return base.Contains_inside_Average_without_GroupBy(async);
+	}
 }