All translated phrases for "warning_definition_X_conversation_text" and "warning_definition_1_conversation_title" were not used. ("warning_definition_X_title" works fine)
See the translation
And the result
Only the master language is used
I cannot reproduce this. I've translated the warnings in both languages that I have setup locally (basically just adding extra things to it) and the default text of the conversation changes as expected based on the language I'm using.
There was a miscommunication here. The edit form always shows the master version of the phrase. The per language translations will be used in user-facing scenarios. (The master value can always be edited if preferred.)