If you close a suggestion by applying the tag defined in the ACP (CLOSE for example) and you reopen the suggestion by removing the tag you have the right to respond to the suggestion again but the message indicating suggestion closed remains (even after refreshing the page).
Setting a prefix to close voting for suggestion threads prevents voting but doesn't display the phrase: {{ phrase('suggestion_closed_votes_not_accepted') }} Dumping $suggestionInfo for a thread with an implemented prefix returns this: Dumping $suggestionInfo for a thread with a closed...