diff --git a/00-META/process/08-small-fixes.md b/00-META/process/08-small-fixes.md
index 149a2612..b2f6d95d 100644
--- a/00-META/process/08-small-fixes.md
+++ b/00-META/process/08-small-fixes.md
@@ -62,6 +62,15 @@ done-when from holding, and that fault is in the same files, it is taken into th
 request with a review round of its own. A fault in other code is opened as an issue of its own, and the first
 issue waits for it (issue 937: mesh-catalog #335 was taken in; issue 943 was opened).
 
+**A fix that moves a file to a new filler compares the values first.** When a fix makes a module's file filled a
+new way for the first time (the provisioner client in place of the controller, a provider's entry in place of a
+composed value), the fix lists every value the old way put into that file on each machine it reaches and shows,
+in its review, that the new way gives the same values, or says which differ and why. A difference nobody looked
+at is an outage: on 2026-10-16 the forge and the identity provider on the control node were down for 17 minutes
+because postgres's consumers were served the port inside its container instead of the port it is published on
+(issue 957). The comparison is read from the machines (the file as it is today) before the merge, not from the
+code.
+
 ## Bounds
 
 | Waiting on | Bound | Past the bound |