diff --git a/async.zsh b/async.zsh
index 1257029..8cd828e 100644
--- a/async.zsh
+++ b/async.zsh
@@ -36,7 +36,7 @@ _async_job() {
 		read -r -k 1 -p tok || exit 1
 
 		# Return output (<job_name> <return_code> <stdout> <duration> <stderr>).
-		print -r -n - ${(q)1} $ret ${(q)stdout} $duration
+		print -r -n - $'\0'${(q)1} $ret ${(q)stdout} $duration
 	} 2> >(stderr=$(cat) && print -r -n - " "${(q)stderr}$'\0')
 
 	# Unlock mutex by inserting a token.
@@ -245,13 +245,15 @@ async_process_results() {
 			if (( $#items == 5 )); then
 				items+=($has_next)
 				$callback "${(@)items}"  # Send all parsed items to the callback.
+				(( num_processed++ ))
+			elif [[ -z $items ]]; then
+				# Empty items occur between results due to double-null ($'\0\0')
+				# caused by commands being both pre and suffixed with null.
 			else
 				# In case of corrupt data, invoke callback with *async* as job
 				# name, non-zero exit status and an error message on stderr.
 				$callback "async" 1 "" 0 "$0:$LINENO: error: bad format, got ${#items} items (${(q)items})" $has_next
 			fi
-
-			(( num_processed++ ))
 		done
 	done
 
diff --git a/async_test.zsh b/async_test.zsh
index 0791fc7..ba55c58 100644
--- a/async_test.zsh
+++ b/async_test.zsh
@@ -7,8 +7,8 @@ test__async_job_print_hi() {
 	local line
 	local -a out
 	line=$(_async_job print hi)
-	# Remove trailing null, parse, unquote and interpret as array.
-	line=$line[1,$#line-1]
+	# Remove leading/trailing null, parse, unquote and interpret as array.
+	line=$line[2,$#line-1]
 	out=("${(@Q)${(z)line}}")
 
 	coproc exit
@@ -396,8 +396,10 @@ test_async_flush_jobs() {
 	# TODO: Confirm that they no longer exist in the process tree.
 	local output
 	output="${(Q)$(ASYNC_DEBUG=1 async_flush_jobs test)}"
-	[[ $output = *'print_four 0 4'* ]] || {
-		t_error "want discarded output 'print_four 0 4' when ASYNC_DEBUG=1, got ${(Vq-)output}"
+	# NOTE(mafredri): First 'p' in print_four is lost when null-prefixing
+	# _async_job output.
+	[[ $output = *'rint_four 0 4'* ]] || {
+		t_error "want discarded output 'rint_four 0 4' when ASYNC_DEBUG=1, got ${(Vq-)output}"
 	}
 
 	# Check that the killed job did not produce output.