The AIA Code of Ethics has a rule that actually covers this issue:
Rule 4.201 Members shall not make misleading, deceptive or false statements or claims about their professional qualifications, experience, or performance and shall accurately state the scope and nature of their responsibilities in connection with work for which they are claiming credit.
Commentary: This rule is meant to prevent Members from claiming or implying credit for work which they did not do, misleading others, and denying other participants in a project their proper share of credit.
If Architect A is an AIA member I would point out to them their need to correct this misinformation and, if no response, you have an ethical duty to report this violation.
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Alice Schuler AIA
architect
Kuklinski+Rappe Architects
Chicago IL
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