diff --git a/src/configs/limits.yaml b/src/configs/limits.yaml
index 33d569e7..37ec6ab0 100644
--- a/src/configs/limits.yaml
+++ b/src/configs/limits.yaml
@@ -19,13 +19,17 @@ limits:
     value: 4
     per_user: true
 
-    # queue-scoped memory cap, percentage of total mem resource
+    # queue-scoped memory cap, percentage of currently-available mem resource
+    # (bug-1831: percent-based value is a 0-1 fraction, not a 0-100 number --
+    # 0.5 = 50%, matching the convention limit2/limits2's original hardcoded
+    # C literal established; the previous "value: 50" here silently computed
+    # 5000% of the resource, a cap that could never actually bind)
   - name: night_mem_pct
     queues:
       members:
         - night
     resname: mem
-    value: 50
+    value: 0.5
     percent: true
 
     # host-scoped cap, applied per host in hg1