Shadow provides peer to peer engagement software, which is being used by the Buttigieg campaign. Just because the same software is being used in Iowa doesn't mean there is a conflict of interest.
I think the standard is to avoid the appearance of a conflict, not to have plausible deniability. I think the person’s point is that it doesn’t look good, and this is the kind of scenario where _you need everything to look good_, because when shit like this happens, it erodes confidence all the more.