routing: deep copy any transaciton we obtain from GetBlock call.

routing/chainview/bitcoind.go

@@ -264,7 +264,7 @@ func (b *BitcoindFilteredChainView) chainFilterer() {
 					continue
 				}
 
-				filteredTxns = append(filteredTxns, tx)
+				filteredTxns = append(filteredTxns, tx.Copy())
 				txAlreadyFiltered = true
 			}
 		}

routing/chainview/btcd.go

@@ -283,7 +283,7 @@ func (b *BtcdFilteredChainView) chainFilterer() {
 					continue
 				}
 
-				filteredTxns = append(filteredTxns, tx)
+				filteredTxns = append(filteredTxns, tx.Copy())
 				txAlreadyFiltered = true
 
 			}

routing/chainview/neutrino.go

@@ -296,7 +296,7 @@ func (c *CfFilteredChainView) FilterBlock(blockHash *chainhash.Hash) (*FilteredB
 			if ok {
 				filteredBlock.Transactions = append(
 					filteredBlock.Transactions,
-					tx.MsgTx(),
+					tx.MsgTx().Copy(),
 				)
 
 				c.filterMtx.Lock()