asterisk warnings on 1.2.30

Hello,
I was using asterisk 1.2.30.2 to 1.2.30.4 recently and I am quite surprised about this messages
edure ast_waitfor_nandfds
May 23 21:17:00 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'SIP/cc104-0859a410', already blocked by thread 74025872 in procedure ast_waitfor_nandfds
May 23 21:17:00 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'Local/58600052@default-8c29,2', already blocked by thread 15895440 in procedure ast_waitfor_nandfds
May 23 21:17:50 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'SIP/cc104-0859a410', already blocked by thread 74025872 in procedure ast_waitfor_nandfds
May 23 21:17:50 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'Local/58600052@default-8c29,2', already blocked by thread 15895440 in procedure ast_waitfor_nandfds
I don't get those warnings on asterisk 1.2.31
Any ideas about this one?
I was using asterisk 1.2.30.2 to 1.2.30.4 recently and I am quite surprised about this messages
edure ast_waitfor_nandfds
May 23 21:17:00 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'SIP/cc104-0859a410', already blocked by thread 74025872 in procedure ast_waitfor_nandfds
May 23 21:17:00 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'Local/58600052@default-8c29,2', already blocked by thread 15895440 in procedure ast_waitfor_nandfds
May 23 21:17:50 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'SIP/cc104-0859a410', already blocked by thread 74025872 in procedure ast_waitfor_nandfds
May 23 21:17:50 WARNING[17107]: channel.c:2290 ast_write: Thread 10976144 Blocking 'Local/58600052@default-8c29,2', already blocked by thread 15895440 in procedure ast_waitfor_nandfds
I don't get those warnings on asterisk 1.2.31
Any ideas about this one?