Error: Trying to link nonexistent states with ACX file

[ftyers]

$ lt-comp lr apertium-scn.scn.dix scn.automorf.bin apertium-scn.scn.acx
Error: Trying to link nonexistent states (-1, 21, 0)

$ lt-comp lr apertium-scn.scn.dix scn.automorf.bin 
apostrophes@postblank 166 230
final@inconditional 34 117
main@standard 38215 90951

Here is a minimal diff of a working .acx vs. not working one:

$ git diff apertium-scn.scn.acx
diff --git a/apertium-scn.scn.acx b/apertium-scn.scn.acx
index b07057a..cd74b41 100644
--- a/apertium-scn.scn.acx
+++ b/apertium-scn.scn.acx
@@ -34,10 +34,12 @@
     <equiv-char value="í"/>
   </char>
 
+<!--
   <char value="ò">
     <equiv-char value="o"/>
     <equiv-char value="ó"/>
   </char>
+-->
 
   <char value="ù">
     <equiv-char value="u"/>

The problem is probably in Compiler::matchTransduction().