diff --git a/packages/backend/src/server/api/mastodon/helpers/notification.ts b/packages/backend/src/server/api/mastodon/helpers/notification.ts
index aced5e6080..3b641067f1 100644
--- a/packages/backend/src/server/api/mastodon/helpers/notification.ts
+++ b/packages/backend/src/server/api/mastodon/helpers/notification.ts
@@ -26,10 +26,11 @@ function normalizeObjectArgs(q: Record<string, string>) {
 		if (k.endsWith("]")) {
 			const segments = k.split("[").map((p) => p.replace(/]$/g, ""));
 			let d = dict;
-			for (let i = 0; i < segments.length - 1; i++) {
+			for (let i = 0; i < segments.length - 2; i++) {
 				if (!(segments[i] in d)) d[segments[i]] = {};
 				d = d[segments[i]];
 			}
+			d[segments[segments.length - 1]] = q[k];
 		} else {
 			dict[k] = q[k];
 		}