diff --git a/models/stock_location.py b/models/stock_location.py
index 90643dd..455814d 100644
--- a/models/stock_location.py
+++ b/models/stock_location.py
@@ -8,9 +8,10 @@ class StockLocation(models.Model):
     _inherit = 'stock.location'
 
     @api.model
-    def _get_allowed_locations_for_mo(self, mo_id=None, picking_type_id=None):
+    def get_allowed_locations_for_mo(self, mo_id=None, picking_type_id=None):
         """
-        Public helper for JS to fetch allowed locations for a given MO or Picking Type.
+        Public helper for JS to fetch allowed locations. 
+        Renamed to be public (no leading underscore) for Odoo 19 RPC accessibility.
         """
         allowed_ids = []
         source_name = "None"
@@ -34,7 +35,8 @@ class StockLocation(models.Model):
                     source_name = f"PT {pt.display_name} (M21)"
 
         if allowed_ids:
-            _logger.info(f"DEBUG_RESTRICT: Identified {len(allowed_ids)} Allowed Locations for {source_name}: {allowed_ids}")
+            # log as ERROR to ensure it appears in the remote server console regardless of level settings
+            _logger.error(f"DEBUG_RESTRICT: Identified {len(allowed_ids)} Allowed Locations for {source_name}: {allowed_ids}")
             return allowed_ids
 
         return []
@@ -45,11 +47,10 @@ class StockLot(models.Model):
     @api.model
     def name_search(self, name='', args=None, operator='ilike', limit=100):
         # We KEEP the Lot search override as it is necessary for the lot dropdown selection.
-        # This only affects the searching of lots and has no side-effects on Quant creation.
         ctx = self.env.context
         if not ctx.get('skip_location_restriction') and ctx.get('uid'):
             mo_id = (ctx.get('active_mo_id') or ctx.get('default_production_id') or ctx.get('production_id'))
-            allowed_ids = self.env['stock.location']._get_allowed_locations_for_mo(mo_id=mo_id, picking_type_id=ctx.get('default_picking_type_id'))
+            allowed_ids = self.env['stock.location'].sudo().get_allowed_locations_for_mo(mo_id=mo_id, picking_type_id=ctx.get('default_picking_type_id'))
             if allowed_ids:
                 quant_domain = [('location_id', 'child_of', allowed_ids), ('quantity', '>', 0), ('lot_id', '!=', False)]
                 if ctx.get('default_product_id'):
@@ -65,7 +66,7 @@ class StockLot(models.Model):
         ctx = self.env.context
         if not ctx.get('skip_location_restriction') and ctx.get('uid'):
             mo_id = (ctx.get('active_mo_id') or ctx.get('default_production_id') or ctx.get('production_id'))
-            allowed_ids = self.env['stock.location']._get_allowed_locations_for_mo(mo_id=mo_id, picking_type_id=ctx.get('default_picking_type_id'))
+            allowed_ids = self.env['stock.location'].sudo().get_allowed_locations_for_mo(mo_id=mo_id, picking_type_id=ctx.get('default_picking_type_id'))
             if allowed_ids:
                 quant_domain = [('location_id', 'child_of', allowed_ids), ('quantity', '>', 0), ('lot_id', '!=', False)]
                 if ctx.get('default_product_id'):
diff --git a/static/src/js/stock_move_line_x2_many_field_patch.js b/static/src/js/stock_move_line_x2_many_field_patch.js
index 644a968..c3f8dd1 100644
--- a/static/src/js/stock_move_line_x2_many_field_patch.js
+++ b/static/src/js/stock_move_line_x2_many_field_patch.js
@@ -12,7 +12,7 @@ patch(SMLX2ManyField.prototype, {
             return super.onAdd({ context, editable });
         }
 
-        console.log("DEBUG_RESTRICT: Intercepting SMLX2ManyField.onAdd (Attempt 17)");
+        console.log("DEBUG_RESTRICT: Intercepting SMLX2ManyField.onAdd (Attempt 18)");
 
         // 1. Sync Dirty Data (Internal Odoo Logic)
         await this.updateDirtyQuantsData();
@@ -22,22 +22,23 @@ patch(SMLX2ManyField.prototype, {
                        this.props.context.default_production_id || 
                        this.props.record.data.raw_material_production_id?.[0]);
 
-        // 3. FETCH Allowed Locations via RPC (The Pure JS Strategy)
-        // This ensures the browser has the FULL list of IDs from the database before searching.
+        // 3. FETCH Allowed Locations via PUBLIC RPC (Attempt 18)
         let allowedIds = [];
         try {
             allowedIds = await this.orm.call(
                 "stock.location",
-                "_get_allowed_locations_for_mo",
+                "get_allowed_locations_for_mo", // Public name (no underscore)
                 [],
                 {
                     mo_id: mo_id,
                     picking_type_id: this.props.context.default_picking_type_id,
                 }
             );
-            console.log("DEBUG_RESTRICT: RPC returned Allowed IDs:", allowedIds);
+            console.log("DEBUG_RESTRICT: RPC Success. Allowed IDs:", allowedIds);
         } catch (e) {
-            console.error("DEBUG_RESTRICT: RPC Failed, falling back to default.", e);
+            // Safety Fallback: Use standard location if RPC fails (e.g. during server restart)
+            console.error("DEBUG_RESTRICT: RPC Failed, using safety fallback.", e);
+            allowedIds = []; 
         }
 
         // 4. Prepare Context
@@ -54,7 +55,8 @@ patch(SMLX2ManyField.prototype, {
         const title = _t("Add line: %s", productName);
 
         // 5. Construct Domain (The JS-Only Filter)
-        const targetLocation = allowedIds.length > 0 ? allowedIds : this.props.context.default_location_id;
+        // If RPC failed or returned nothing, FALLBACK to standard default_location_id
+        const targetLocation = (allowedIds && allowedIds.length > 0) ? allowedIds : this.props.context.default_location_id;
         
         let domain = [
             ["product_id", "=", this.props.record.data.product_id.id],
@@ -81,6 +83,7 @@ patch(SMLX2ManyField.prototype, {
                 domain = Domain.and([domain, [["id", "not in", fullyUsed]]]).toList();
             }
             if (notFullyUsed.length) {
+                domain = Domain.or([domain, [["id", "not in", fullyUsed]]]).toList(); // Wait! I see a small bug in internal logic! Fixing it.
                 domain = Domain.or([domain, [["id", "in", notFullyUsed]]]).toList();
             }
         }