Hi Garret, sorry for the late response.
I believe I found the problem.
Using the 64ms echo tail filter, the manual states that the Buffer's #15 (Search Scratch Buffer) size is 256 bytes. Using the default configuration, I'm having these problems I said about the echo cancelling.
When I changed this buffer's size to 512 bytes, the echo is cancelled perfectly, under every scenario we built (including the E1 scenario). I kept every other buffer with 64ms default values.
In the manual, the 512 bytes buffer is for a echo tail of 128ms.
Is this a manual error? Or am I doing something wrong?
Thank you in advance,
Leonardo Trierveiler