diff --git a/services/feed/action.go b/services/feed/action.go
index f178e99001..2d07f39284 100644
--- a/services/feed/action.go
+++ b/services/feed/action.go
@@ -488,6 +488,12 @@ func encodeContent(params ...string) string {
 func abbreviatedComment(comment string) string {
 	firstLine := strings.Split(comment, "\n")[0]
 
+	if strings.HasPrefix(firstLine, "```") {
+		// First line is is a fenced code block... with no special abbreviate we would display a blank block, or in the
+		// worst-case a ```mermaid would display an error. Better to omit the comment.
+		return ""
+	}
+
 	truncatedContent, truncatedRight := util.SplitStringAtByteN(firstLine, 200)
 	if truncatedRight != "" {
 		// in case the content is in a Latin family language, we remove the last broken word.
diff --git a/services/feed/action_test.go b/services/feed/action_test.go
index 35b170e95c..48de7995bf 100644
--- a/services/feed/action_test.go
+++ b/services/feed/action_test.go
@@ -185,6 +185,16 @@ func TestAbbreviatedComment(t *testing.T) {
 			input:    "Interesting point, here's a digram with my thoughts:\n```mermaid\ngraph LR\n   a -->|some text| b\n```",
 			expected: "Interesting point, here's a digram with my thoughts:",
 		},
+		{
+			name:     "block start",
+			input:    "```\n# This file describes the expected reviewers for a PR based on the changed\n# files.\n```\n\nI think this comment is wrong...",
+			expected: "",
+		},
+		{
+			name:     "labeled block start",
+			input:    "```mermaid\ngraph LR\n   a -->|some text| b\n```",
+			expected: "",
+		},
 	}
 
 	for _, tt := range tests {