diff --git a/src/block_proof.cpp b/src/block_proof.cpp
index 0c1a279d68..78a1765329 100644
--- a/src/block_proof.cpp
+++ b/src/block_proof.cpp
@@ -10,10 +10,17 @@
 #include <script/interpreter.h>
 #include <script/generic.hpp>
 
-bool CheckChallenge(const CBlockHeader& block, const CBlockIndex& indexLast, const Consensus::Params& params)
+bool CheckChallenge(const CBlockHeader& block, CBlockIndex& indexLast, const Consensus::Params& params)
 {
     if (g_signed_blocks) {
-        return block.proof.challenge == indexLast.get_proof().challenge;
+        if (indexLast.trimmed()) {
+            // Create a dummy block index to temporarily hold the untrimmed data
+            CBlockIndex tmp_index;
+            const CBlockIndex* pindexUntrimmed = indexLast.untrim_to(&tmp_index);
+            return block.proof.challenge == pindexUntrimmed->get_proof().challenge;
+        } else {
+            return block.proof.challenge == indexLast.get_proof().challenge;
+        }
     } else {
         return block.nBits == GetNextWorkRequired(&indexLast, &block, params);
     }
diff --git a/src/block_proof.h b/src/block_proof.h
index 273699f37f..9dbfb21ad8 100644
--- a/src/block_proof.h
+++ b/src/block_proof.h
@@ -20,6 +20,6 @@ class CScript;
 /** Check on header proof, depending on chain type, PoW or signed **/
 bool CheckProof(const CBlockHeader& block, const Consensus::Params&);
 bool CheckProofSignedParent(const CBlockHeader& block, const Consensus::Params&);
-bool CheckChallenge(const CBlockHeader& block, const CBlockIndex& indexLast, const Consensus::Params&);
+bool CheckChallenge(const CBlockHeader& block, CBlockIndex& indexLast, const Consensus::Params&);
 
 #endif // BITCOIN_BLOCK_PROOF_H
diff --git a/src/validation.cpp b/src/validation.cpp
index 53cf2cc0c2..11e9ce7884 100755
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3860,7 +3860,7 @@ static bool ContextualCheckDynaFedHeader(const CBlockHeader& block, BlockValidat
  *  in ConnectBlock().
  *  Note that -reindex-chainstate skips the validation that happens here!
  */
-static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, BlockManager& blockman, const ChainstateManager& chainman, const CBlockIndex* pindexPrev, int64_t nAdjustedTime) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
+static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, BlockManager& blockman, const ChainstateManager& chainman, CBlockIndex* pindexPrev, int64_t nAdjustedTime) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
     AssertLockHeld(::cs_main);
     assert(pindexPrev != nullptr);
@@ -3868,6 +3868,7 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidatio
 
     // Check proof of work target or non-dynamic signblockscript if necessary
     const Consensus::Params& consensusParams = chainman.GetConsensus();
+
     if (!DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_DYNA_FED) && !CheckChallenge(block, *pindexPrev, consensusParams))
         return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "bad-diffbits", "incorrect proof of work");