diff --git a/api/src/controllers/fields.ts b/api/src/controllers/fields.ts
index 402c544d97..efa9c89181 100644
--- a/api/src/controllers/fields.ts
+++ b/api/src/controllers/fields.ts
@@ -74,7 +74,9 @@ const newFieldSchema = Joi.object({
 		default_value: Joi.any(),
 		max_length: [Joi.number(), Joi.string(), Joi.valid(null)],
 		is_nullable: Joi.bool(),
-	}).unknown(),
+	})
+		.unknown()
+		.allow(null),
 	meta: Joi.any(),
 });
 
@@ -158,7 +160,9 @@ const updateSchema = Joi.object({
 		default_value: Joi.any(),
 		max_length: [Joi.number(), Joi.string(), Joi.valid(null)],
 		is_nullable: Joi.bool(),
-	}).unknown(),
+	})
+		.unknown()
+		.allow(null),
 	meta: Joi.any(),
 }).unknown();
 
diff --git a/app/src/modules/settings/routes/data-model/get-local-type.ts b/app/src/modules/settings/routes/data-model/get-local-type.ts
index fefaa4eef8..419d0ce43d 100644
--- a/app/src/modules/settings/routes/data-model/get-local-type.ts
+++ b/app/src/modules/settings/routes/data-model/get-local-type.ts
@@ -19,7 +19,7 @@ export function getLocalTypeForField(
 	if (relations.length === 1) {
 		const relation = relations[0];
 		if (relation.one_collection === 'directus_files') return 'file';
-		if (relation.many_collection === collection) return 'm2o';
+		if (relation.many_collection === collection && relation.many_field === field) return 'm2o';
 		return 'o2m';
 	}