Just use subdivision-1.

src/queries/analytics/events/saveEvent.ts

@@ -138,8 +138,8 @@ async function clickhouseQuery(data: {
     session_id: sessionId,
     event_id: uuid(),
     country: country ? country : null,
-    subdivision1: country && subdivision1 ? `${country}-${subdivision1}` : null,
-    subdivision2: subdivision2 ? subdivision2 : null,
+    subdivision1: subdivision1 ?? null,
+    subdivision2: subdivision2 ?? null,
     city: city ? city : null,
     url_path: urlPath?.substring(0, URL_LENGTH),
     url_query: urlQuery?.substring(0, URL_LENGTH),

src/queries/analytics/sessions/createSession.ts

@@ -30,7 +30,7 @@ export async function createSession(data: Prisma.SessionCreateInput) {
         screen,
         language,
         country,
-        subdivision1: country && subdivision1 ? `${country}-${subdivision1}` : null,
+        subdivision1,
         subdivision2,
         city,
       },