update with no effect

[Lars Hecking]

 I have started seeing these entries in named.log:

29-Mar-2009 05:02:35.467 general: warning: update with no effect
29-Mar-2009 05:02:35.468 general: warning: update with no effect
29-Mar-2009 05:02:35.469 general: warning: update with no effect
29-Mar-2009 05:02:35.470 general: warning: update with no effect
29-Mar-2009 05:02:35.471 general: warning: update with no effect
29-Mar-2009 05:02:35.472 general: warning: update with no effect
29-Mar-2009 05:02:35.478 general: warning: update with no effect
29-Mar-2009 05:02:35.479 general: warning: update with no effect
29-Mar-2009 05:02:35.480 general: warning: update with no effect
29-Mar-2009 05:02:35.481 general: warning: update with no effect
29-Mar-2009 05:02:35.482 general: warning: update with no effect
29-Mar-2009 05:02:35.483 general: warning: update with no effect
29-Mar-2009 05:02:35.484 general: warning: update with no effect

 What is that about? This is bind 9.4.2-P2 on Solaris 8.