Defective HTTP request! and garbled messages

[LLG-Steve]

I am getting a rash of

2/18/15 5:00:37.900 PM com.avast.proxy[985]: Defective HTTP request!
2/18/15 5:00:37.900 PM com.avast.proxy[985]: ��
yX�z[;�`6�m[b�.=�`V0�o+�`=�-[.�s
1�o[b�0Wh�-[+�q   7�u<�n6�b
1�o-!�d
z�Z[;�m:�bu�n4�oz�|
2/18/15 5:02:48.216 PM com.avast.proxy[985]: Defective HTTP request!
2/18/15 5:02:48.216 PM com.avast.proxy[985]: �����*���B���O������^���K���B���ȫ�O���E���է�ȫ�_���X���i���O���E�ݹZ������K���K���Z���C���w�

in my console logs. 

One garbled message appeared to have a clear text HTTP header in it, and might have been from an Amazon server.

How can I diagnose these messages?

Model Name:   Mac Pro
Model Identifier:   MacPro5,1

System Version:   OS X 10.10.2 (14C109)
Kernel Version:   Darwin 14.1.0

Avast Version:   10.6 (43623)
Obtained from:   Identified Developer
Last Modified:   2/9/15, 11:01 AM

[tumic]

Those messages are debug messages about HTTP requests/responses the webshield can not parse. Usually all you can do about this is to report the causing URL (and the exact browser version) to us, so we can analyze the issue and eventually do some fixes in the webshield.