Avast is now adding the above advertising to all my outgoing email. I pay for Avast, so I shouldn’t have to provide free advertising for it. It is unprofessional and inappropriate for this 3rd-party advertising to appear in my business email. (This apparently just started, and I’ve been called out about it.)
[edit] Actually, I found I could disable it in the Anti-Virus options.
As for being in Avast for “quite a while”, the emails I sent before today did not have the banner. The banner started appearing today. I have Avast Pro Anti-Virus.
AvastUI > Settings > General > uncheck the ‘Enable Avast email signature.’
That should override the AvastUI > Settings > Component > Mail Shield > Behaviour settings.
The reason this changed was because the Web Shield is/was able to do the same thing with web based email and there were two sets of settings, then avast added it to the mail settings for ease of access.