[exim] Is not honoring bounces-to violation of RFC?

I know this question is not specifically germane to Exim but everyone on
this list has extensive experience with bouncing policies.

If a receiver of campaign emails (that promotes itself as an email
security service) sends bounces to "reply-to" rather than "bounces-to"
as a policy despite bounces-to present in all campaign emails headers,
would this be considered a violation of RFCs?