New stability issues and phenomena are emerging with the more important part of Power Electronics Interfaced Resources (PEIR), and in particular slow converter driven interactions have been observed in a number of real situations. Their impact – until now – has been limited due to either the tripping of the units or manual effective counteractions. However, all the indicators (SCR, ESCR, etc.), used to measure potential risks of interactions, reach low values in future scenarios until the grid-forming components become predominant in all the system. In this context, it seems necessary to answer these two important questions: 1. Is there a risk of propagation of the adverse interactions through the system or will it remain limited to a few installations? 2. How to understand, explain and reproduce the issue on small test cases?