diff --git a/client/package-lock.json b/client/package-lock.json
index c7d59b06c..4644d9370 100644
--- a/client/package-lock.json
+++ b/client/package-lock.json
@@ -1,12 +1,12 @@
 {
 	"name": "client",
-	"version": "3.9.0",
+	"version": "3.9.1",
 	"lockfileVersion": 3,
 	"requires": true,
 	"packages": {
 		"": {
 			"name": "client",
-			"version": "3.9.0",
+			"version": "3.9.1",
 			"dependencies": {
 				"@csstools/css-tokenizer": "^3.0.4",
 				"@emotion/react": "^11.13.3",
diff --git a/client/package.json b/client/package.json
index 685b37db1..4fc8b2634 100644
--- a/client/package.json
+++ b/client/package.json
@@ -1,7 +1,7 @@
 {
 	"name": "client",
 	"private": true,
-	"version": "3.9.0",
+	"version": "3.9.1",
 	"type": "module",
 	"scripts": {
 		"dev": "vite",
diff --git a/server/src/db/migration/0002_convertChecksToTimeSeries.ts b/server/src/db/migration/0002_convertChecksToTimeSeries.ts
index 91170050b..0c171744f 100644
--- a/server/src/db/migration/0002_convertChecksToTimeSeries.ts
+++ b/server/src/db/migration/0002_convertChecksToTimeSeries.ts
@@ -1,5 +1,5 @@
 import mongoose from "mongoose";
-import type { Document, AnyBulkWriteOperation } from "mongodb";
+import type { Document } from "mongodb";
 
 const CHECKS_COLLECTION = "checks";
 const BACKUP_COLLECTION = "checks_backup";
@@ -144,7 +144,11 @@ const migrateBackupData = async (backedUp: boolean): Promise<MigrationStats> =>
 
 		stats.totalSource = await source.countDocuments();
 		const cursor = source.find();
-		const operations: AnyBulkWriteOperation<Document>[] = [];
+		// Derive the op type from the exact bulkWrite we call so it matches whichever `mongodb` copy
+		// Mongoose resolves (a fresh Docker/multiarch install nests its own under mongoose/node_modules,
+		// distinct from the top-level one — importing AnyBulkWriteOperation from "mongodb" picks the wrong copy).
+		type BulkOp = Parameters<typeof target.bulkWrite>[0][number];
+		const operations: BulkOp[] = [];
 		const invalidDocs: Document[] = [];
 
 		while (await cursor.hasNext()) {
diff --git a/server/src/db/migration/0007_migrateMaintenanceWindowMonitorIdToArray.ts b/server/src/db/migration/0007_migrateMaintenanceWindowMonitorIdToArray.ts
index 437c66704..7f0d22e0e 100644
--- a/server/src/db/migration/0007_migrateMaintenanceWindowMonitorIdToArray.ts
+++ b/server/src/db/migration/0007_migrateMaintenanceWindowMonitorIdToArray.ts
@@ -1,5 +1,4 @@
 import mongoose from "mongoose";
-import type { AnyBulkWriteOperation, Document } from "mongodb";
 import type { ILogger } from "@/utils/logger.js";
 import MaintenanceWindowModel from "../../domain/maintenance-windows/maintenance-window.model.js";
 
@@ -65,7 +64,11 @@ export async function migrateMaintenanceWindowMonitorIdToArray(logger: ILogger):
 			return;
 		}
 
-		const bulkOps: AnyBulkWriteOperation<Document>[] = [];
+		// Derive the op type from the exact bulkWrite we call, so it always matches whichever `mongodb`
+		// copy Mongoose resolves (a fresh Docker install nests its own under mongoose/node_modules,
+		// distinct from the top-level one — importing the type from "mongodb" picks the wrong copy).
+		type BulkOp = Parameters<typeof MaintenanceWindowModel.collection.bulkWrite>[0][number];
+		const bulkOps: BulkOp[] = [];
 		let originalDocCount = 0;
 
 		for (const group of groups) {