Ah, thanks, I did miss that the concern isn’t about duplicate content but rather duplicate title and meta description warnings.
For Discourse at least, those are more like “notices” than warnings. Kind of like “if you didn’t know about this you should check to make sure it’s OK and if not fix”. You can safely ignore those as a topic discussion shouldn’t meander so much that what would be appropriate for the first posts would not apply to all further posts in the topic.
For example if the “page 1” posts are about “round red widgets” and by “page 2” the posts are about “square green sprockets” members should be urged to stay on topic or the discussion should be split into separate topics.