diff --git a/polkadot/node/core/dispute-coordinator/src/initialized.rs b/polkadot/node/core/dispute-coordinator/src/initialized.rs
index dd7aef19f6ed6b972149067d6540694c404cc4c0..2d8e15064e4736776864b3a2ecfb8b37960002ef 100644
--- a/polkadot/node/core/dispute-coordinator/src/initialized.rs
+++ b/polkadot/node/core/dispute-coordinator/src/initialized.rs
@@ -1271,7 +1271,7 @@ impl Initialized {
 		if import_result.has_fresh_byzantine_threshold_against() {
 			let blocks_including = self.scraper.get_blocks_including_candidate(&candidate_hash);
 			for (parent_block_number, parent_block_hash) in &blocks_including {
-				gum::trace!(
+				gum::warn!(
 					target: LOG_TARGET,
 					?candidate_hash,
 					?parent_block_number,
@@ -1282,7 +1282,7 @@ impl Initialized {
 			if blocks_including.len() > 0 {
 				ctx.send_message(ChainSelectionMessage::RevertBlocks(blocks_including)).await;
 			} else {
-				gum::debug!(
+				gum::warn!(
 					target: LOG_TARGET,
 					?candidate_hash,
 					?session,
diff --git a/polkadot/node/core/dispute-coordinator/src/scraping/candidates.rs b/polkadot/node/core/dispute-coordinator/src/scraping/candidates.rs
index 38956700545cd46971120a415310880c2b6c3b9f..b1870164cb88cadaad7019ca0be5a0f23f5a3454 100644
--- a/polkadot/node/core/dispute-coordinator/src/scraping/candidates.rs
+++ b/polkadot/node/core/dispute-coordinator/src/scraping/candidates.rs
@@ -135,11 +135,14 @@ impl ScrapedCandidates {
 	}
 
 	pub fn insert(&mut self, block_number: BlockNumber, candidate_hash: CandidateHash) {
-		self.candidates.insert(candidate_hash);
-		self.candidates_by_block_number
+		if self
+			.candidates_by_block_number
 			.entry(block_number)
 			.or_default()
-			.insert(candidate_hash);
+			.insert(candidate_hash)
+		{
+			self.candidates.insert(candidate_hash);
+		}
 	}
 
 	// Used only for tests to verify the pruning doesn't leak data.
@@ -159,6 +162,8 @@ mod scraped_candidates_tests {
 		let mut candidates = ScrapedCandidates::new();
 		let target = CandidateHash(BlakeTwo256::hash(&vec![1, 2, 3]));
 		candidates.insert(1, target);
+		// Repeated inserts at same height should be fine:
+		candidates.insert(1, target);
 
 		assert!(candidates.contains(&target));