Disabling transactional notification doesn’t work

Hi! Thx for great addon. I ran into a small problem using it – the “Disable” option doesn’t work for me for some reason. I try to disable the “User Email Changed – for user” notification, but it still gets sent.
1. What is the possible reason for this, can you point me where to look at?
2. Currently I solved the issue by leaving this notification enabled but keeping the message text blank. In this case, the email doesn’t get sent, though the outgoing emails log (provided by firewall addon) has the corresponding record as if it was sent. Does this solution have any possible issues I don’t know of, or I can live with it for some time?