diff --git a/k8s/applications/temporal/temporal-values.yaml b/k8s/applications/temporal/temporal-values.yaml
index 7d44ee9..c48acae 100644
--- a/k8s/applications/temporal/temporal-values.yaml
+++ b/k8s/applications/temporal/temporal-values.yaml
@@ -107,8 +107,12 @@ server:
           maxConns: 20
           maxIdleConns: 10
           maxConnLifetime: "1h"
-          connectAttributes:
-            tx_isolation: "READ-COMMITTED"
+          # NOTE: no `connectAttributes: { tx_isolation: ... }` here — tx_isolation
+          # is a MySQL-only connection parameter. The Postgres `pq` driver rejects
+          # it ("unrecognized configuration parameter"), which killed every DB
+          # connection (schema-setup job AND server) with the misleading
+          # "no usable database connection found". Postgres defaults to READ
+          # COMMITTED isolation anyway, so nothing is lost by omitting it.
       visibility:
         driver: "sql"
         sql: