diff --git a/src/app/api/plant-hours/import/route.ts b/src/app/api/plant-hours/import/route.ts
index 68ba4d1..e36720c 100644
--- a/src/app/api/plant-hours/import/route.ts
+++ b/src/app/api/plant-hours/import/route.ts
@@ -47,22 +47,42 @@ const MAX_BYTES = 10 * 1024 * 1024; // 10 MB — same as fuel-logs import
 export async function POST(request: Request) {
   const start = Date.now();
 
-  // PB's ClientResponseError has `.data` with field-level validation
-  // details. Plain `err.message` is just "Failed to create record." -
-  // useless for diagnosis. Flatten field-level detail into a single
-  // human-readable string so the operator can see which field is
-  // rejecting the row.
+  // PB's ClientResponseError has `.data` whose keys are "data",
+  // "message", "status" — only the inner `.data.data` (or sometimes
+  // `.data.data.fieldErrors`) holds the field-level validation object.
+  // Plain `err.message` is just "Failed to create record." - useless
+  // for diagnosis. Flatten the inner field-level detail into a single
+  // human-readable string so the operator can see WHICH field rejected
+  // the row.
   function formatPbError(err: unknown): string {
     const e = err as {
       message?: string;
-      data?: Record<string, { message?: string; code?: string }>;
+      data?: {
+        data?:
+          | Record<string, { message?: string; code?: string }>
+          | {
+              fieldErrors?: Record<string, { message?: string; code?: string }>;
+            };
+        message?: string;
+      };
     };
     const head = e?.message ?? "Insert failed";
-    if (e?.data && typeof e.data === "object") {
-      const parts = Object.entries(e.data)
-        .map(([field, info]) => `${field}: ${info?.message ?? "invalid"}`)
-        .join("; ");
-      if (parts) return `${head} (${parts})`;
+    const inner =
+      e?.data?.data && typeof e.data.data === "object" ? e.data.data : null;
+    if (inner) {
+      const fieldErrors =
+        "fieldErrors" in inner && inner.fieldErrors ? inner.fieldErrors : inner;
+      if (typeof fieldErrors === "object" && fieldErrors !== null) {
+        const parts = Object.entries(fieldErrors as Record<string, unknown>)
+          .map(([field, info]) => {
+            if (info && typeof info === "object" && "message" in info) {
+              return `${field}: ${(info as { message?: string }).message ?? "invalid"}`;
+            }
+            return `${field}: ${String(info)}`;
+          })
+          .join("; ");
+        if (parts) return `${head} (${parts})`;
+      }
     }
     return head;
   }