message: No ACP during IBD
diff: @@ -2882,7 +2882,7 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
  }
  // Check that the block satisfies checkpoint sync
  - if (!CheckSyncCheckpoint(pindex))
  + if (!IsInitialBlockDownload() && !CheckSyncCheckpoint(pindex))
  return state.Invalid(ValidationInvalidReason::BLOCK_CHECKPOINT, error("%s: rejected by checkpoint sync %s", __func__, block.GetHash().ToString()), REJECT_CHECKPOINT, "bad-block-checkpoint-sync");
  // Move this check from CheckBlock to ConnectBlock as it depends on DGP values
  @@ -4974,7 +4974,7 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationSta
  }
  // Check that the block satisfies checkpoint sync
  - if (!CheckSyncCheckpoint(nullptr, block.GetHash(), nHeight)) {
  + if (!::ChainstateActive().IsInitialBlockDownload() && !CheckSyncCheckpoint(nullptr, block.GetHash(), nHeight)) {
  return state.Invalid(ValidationInvalidReason::BLOCK_CHECKPOINT, error("%s: rejected by checkpoint sync %s", __func__, block.GetHash().ToString()), REJECT_CHECKPOINT, "bad-block-checkpoint-sync");
  }
  @@ -5271,6 +5271,7 @@ bool BlockManager::AcceptBlockHeader(const CBlockHeader& block, CValidationState
  pindex = AddToBlockIndex(block);
  // Check if pending checkpoint relates to the block just added
  + if (!::ChainstateActive().IsInitialBlockDownload())
  AcceptPendingSyncCheckpoint();
  if (ppindex)
  