avast doesn’t strip parts of email newsletters.

It may warn of virus infection, in which case you choose to delete or move to chest, etc. but it doesn’t strip codes (what ever you mean by that?). It may delete an infected attachment, again on your instruction, but it doesn’t strip codes. It may add lines of text to state that your email is clean, again on your instruction/settings, but it doesn’t strip codes.

I think you are getting the picture, someone is obviously adding up 2+2 and getting 5.