Given two graphs, a fundamental task faced by matching algorithms consists of computing either the (Connected) Maximal Common Induced Subgraphs ((C)MCIS) or the (Connected) Maximal Common Edge Subgraphs ((C)MCES). In particular, computing the CMCIS or CMCES reduces to reporting so-called connected cliques in product graphs, a problem for which an algorithm has been presented in a recent paper I. Koch, TCS 250 (1-2), 2001. This algorithm suffers from two problems which are corrected in this note.