diff --git a/C#-and-.NET-docs-supplement.md b/C#-and-.NET-docs-supplement.md
index 7b5b78b..7d8758d 100644
--- a/C#-and-.NET-docs-supplement.md
+++ b/C#-and-.NET-docs-supplement.md
@@ -11,6 +11,10 @@ To save us repeating our complaints about the lack of proper documentation under
 
 see [feature matrix](https://github.com/TASEmulators/BizHawk/wiki/Available-C%23-and-.NET-features) page
 
+## `String.GetHashCode` stability
+
+The `GetHashCode` implementation for strings does not reflect the string's contents, and as such, is not stable between program instances.
+
 ## `System.Drawing.SystemIcons` rendered
 
 [Docs for `SystemIcons`](https://learn.microsoft.com/en-us/dotnet/api/system.drawing.systemicons?view=netframework-4.8) don't include any pictures, so here they are (Win10, Mono 6.12.x):