File dowloaded is corrupted

Hello, sorry i'm new on this forum so i didn't see you archived my post.

Sorry i don't explain clearly all the context.

Our customer chooses to publish several sites using a common public address. The public ip address returns traffic received on the Big ip  which forwards it where to a virtual server (mutual_vs) on port https. This has an ltm policy which redirects traffic based on domain name in the host header of received request to another virtual server vs_app. 

The vs_app is on port https and has one pool member in https. It's configured with 2 http profile (f5-tcp-wan and f5-tcp-lan) ans ssl profiles (clien-side ans server-side), no cookie profile, no ltm policy profile, no irule.  

The external user can access to the website of the v_app without an error page. After authenticated in the website, he can also navigate through the different pages of the site without an error page. In the website he can use a plugin to report information about an incident and download the summary in an excel file.

The file received doesn't have the expected values, but instead there's a copy of the site's html web page. 

In capture file traffic i get : I have the reason for the session reset by the big ip  ---> http Unexpected server data past end of response. 
In ltm log file i see this message : "http_handle_pipelined_data - Invalid action:0x108000 Server sends too much data. serverside..

i tried to troubleshoot by adding an irule in the vs_app to disable http check when Content-Type is application/octet-stream but i continue getting the same error in /var/log/ltm
I finaly modify the vs_app which has now only a  simple tcp profile, no http profile, no ssl profile. But i get the same error.

I notice that when the traffic flow bypass the mutual_vs and go directly through the vs_app (with my last changes) it works as expected fo the customer and the file is as expected.

I need your help to understand what's cause this issue.