asterisk users - Apr 2006 - Major issue: More incompatible frame messages

This is a serious problem!

I have brought up this issue in four previous attempts to get some feedback.
I find it hard to believe that no one else is having this same problem.

Apr 11 13:27:36 NOTICE[4446]: channel.c:1906 ast_read: Dropping incompatible
voice frame on Local/103@sip-00f3,2 of format alaw since our native format
has changed to slin
Apr 11 13:27:36 NOTICE[4446]: channel.c:1906 ast_read: Dropping incompatible
voice frame on Local/103@sip-00f3,2 of format alaw since our native format
has changed to slin
Apr 11 13:27:36 NOTICE[4446]: channel.c:1906 ast_read: Dropping incompatible
voice frame on Local/103@sip-00f3,2 of format alaw since our native format
has changed to slin

This is the third box running 1.2.X that I have seen this on.

This Asterisk install is running nothing but alaw. No call transcoding of
any kind (unless you count voicemail and I assume musiconhold).

There is nothing at all in the WIKI about slin. I know it is the internal
format for asterisk, but why is it even relative here. All SIP UAs are using
alaw, and the PRI is alaw.

Regards to all,
Joe

It seems that the problem only occurs when there is a redirect:
   
 -- Executing Dial("Zap/19-1", "SIP/123|40|t") in new stack
    -- Called 123
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.5
    -- Now forwarding Zap/19-1 to 'Local/103@sip' (thanks to
SIP/123-878b)
    -- Executing Macro("Local/103@sip-1b31,2", "stdexten")
in new stack
    -- Executing Set("Local/103@sip-1b31,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/103@sip-1b31,2",
"aviareps") in new
stack
    -- Executing Dial("Local/103@sip-1b31,2",
"SIP/103|20|t") in new stack
    -- Called 103
Apr 11 14:53:01 NOTICE[8364]: channel.c:1906 ast_read: Dropping incompatible
voice frame on Local/103@sip-1b31,2 of format alaw since our native format
has changed to slin
Apr 11 14:53:01 NOTICE[8364]: channel.c:1906 ast_read: Dropping incompatible
voice frame on Local/103@sip-1b31,2 of format alaw since our native format
has changed to slin

I really hope that someone can shed some light onthis problem.

Joe