diff --git a/graph.c b/graph.c
index 66ae18add8..aaf97069bd 100644
--- a/graph.c
+++ b/graph.c
@@ -1063,7 +1063,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct graph_l
 	int i, j;
 
 	struct commit_list *first_parent = first_interesting_parent(graph);
-	int seen_parent = 0;
+	struct column *parent_col = NULL;
 
 	/*
 	 * Output the post-merge row
@@ -1117,12 +1117,17 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct graph_l
 			graph_line_addch(line, ' ');
 		} else {
 			graph_line_write_column(line, col, '|');
-			if (graph->merge_layout != 0 || i != graph->commit_index - 1)
-				graph_line_addch(line, seen_parent ? '_' : ' ');
+			if (graph->merge_layout != 0 || i != graph->commit_index - 1) {
+				if (parent_col)
+					graph_line_write_column(
+						line, parent_col, '_');
+				else
+					graph_line_addch(line, ' ');
+			}
 		}
 
 		if (col_commit == first_parent->item)
-			seen_parent = 1;
+			parent_col = col;
 	}
 
 	/*
@@ -1219,13 +1224,9 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct graph_l
 			 *
 			 * The space just to the left of this
 			 * branch should always be empty.
-			 *
-			 * The branch to the left of that space
-			 * should be our eventual target.
 			 */
 			assert(graph->mapping[i - 1] > target);
 			assert(graph->mapping[i - 2] < 0);
-			assert(graph->mapping[i - 3] == target);
 			graph->mapping[i - 2] = target;
 			/*
 			 * Mark this branch as the horizontal edge to
diff --git a/t/t4215-log-skewed-merges.sh b/t/t4215-log-skewed-merges.sh
index 18709a723e..5661ed5881 100755
--- a/t/t4215-log-skewed-merges.sh
+++ b/t/t4215-log-skewed-merges.sh
@@ -240,4 +240,75 @@ test_expect_success 'log --graph with octopus merge with column joining its penu
 	EOF
 '
 
+test_expect_success 'log --graph with multiple tips' '
+	git checkout --orphan 6_1 &&
+	test_commit 6_A &&
+	git branch 6_2 &&
+	git branch 6_4 &&
+	test_commit 6_B &&
+	git branch 6_3 &&
+	test_commit 6_C &&
+	git checkout 6_2 && test_commit 6_D &&
+	git checkout 6_3 && test_commit 6_E &&
+	git checkout -b 6_5 6_1 &&
+	git merge --no-ff 6_2 -m 6_F &&
+	git checkout 6_4 && test_commit 6_G &&
+	git checkout 6_3 &&
+	git merge --no-ff 6_4 -m 6_H &&
+	git checkout 6_1 &&
+	git merge --no-ff 6_2 -m 6_I &&
+
+	check_graph 6_1 6_3 6_5 <<-\EOF
+	*   6_I
+	|\
+	| | *   6_H
+	| | |\
+	| | | * 6_G
+	| | * | 6_E
+	| | | | * 6_F
+	| |_|_|/|
+	|/| | |/
+	| | |/|
+	| |/| |
+	| * | | 6_D
+	| | |/
+	| |/|
+	* | | 6_C
+	| |/
+	|/|
+	* | 6_B
+	|/
+	* 6_A
+	EOF
+'
+
+test_expect_success 'log --graph with multiple tips and colors' '
+	test_config log.graphColors red,green,yellow,blue,magenta,cyan &&
+	cat >expect.colors <<-\EOF &&
+	*   6_I
+	<RED>|<RESET><GREEN>\<RESET>
+	<RED>|<RESET> <GREEN>|<RESET> *   6_H
+	<RED>|<RESET> <GREEN>|<RESET> <YELLOW>|<RESET><BLUE>\<RESET>
+	<RED>|<RESET> <GREEN>|<RESET> <YELLOW>|<RESET> * 6_G
+	<RED>|<RESET> <GREEN>|<RESET> <YELLOW>|<RESET> <BLUE>|<RESET> * 6_F
+	<RED>|<RESET> <GREEN>|<RESET><RED>_<RESET><YELLOW>|<RESET><RED>_<RESET><BLUE>|<RESET><RED>/<RESET><GREEN>|<RESET>
+	<RED>|<RESET><RED>/<RESET><GREEN>|<RESET> <YELLOW>|<RESET> <BLUE>|<RESET><GREEN>/<RESET>
+	<RED>|<RESET> <GREEN>|<RESET> <YELLOW>|<RESET><GREEN>/<RESET><BLUE>|<RESET>
+	<RED>|<RESET> <GREEN>|<RESET><GREEN>/<RESET><YELLOW>|<RESET> <BLUE>|<RESET>
+	<RED>|<RESET> <GREEN>|<RESET> * <BLUE>|<RESET> 6_E
+	<RED>|<RESET> * <CYAN>|<RESET> <BLUE>|<RESET> 6_D
+	<RED>|<RESET> <BLUE>|<RESET> <CYAN>|<RESET><BLUE>/<RESET>
+	<RED>|<RESET> <BLUE>|<RESET><BLUE>/<RESET><CYAN>|<RESET>
+	* <BLUE>|<RESET> <CYAN>|<RESET> 6_C
+	<CYAN>|<RESET> <BLUE>|<RESET><CYAN>/<RESET>
+	<CYAN>|<RESET><CYAN>/<RESET><BLUE>|<RESET>
+	* <BLUE>|<RESET> 6_B
+	<BLUE>|<RESET><BLUE>/<RESET>
+	* 6_A
+	EOF
+	git log --color=always --graph --date-order --pretty=tformat:%s 6_1 6_3 6_5 >actual.colors.raw &&
+	test_decode_color <actual.colors.raw | sed "s/ *\$//" >actual.colors &&
+	test_cmp expect.colors actual.colors
+'
+
 test_done