A coherent attached processor proxy (CAPP) participates in coherence communication in a primary coherent system on behalf of an attached processor external to the primary coherent system. The CAPP includes an epoch timer that advances at regular intervals to define epochs of operation of the CAPP. Each of one or more entries in a data structure in the CAPP are associated with a respective epoch. Recovery operations for the CAPP are initiated based on a comparison of an epoch indicated by the epoch timer and the epoch associated with one of the one or more entries in the data structure.