diff --git a/lib/runner/connection/buffer.rb b/lib/runner/connection/buffer.rb
index e8f18e82..dcd01169 100644
--- a/lib/runner/connection/buffer.rb
+++ b/lib/runner/connection/buffer.rb
@@ -51,7 +51,7 @@ class Runner::Connection::Buffer
     # We split lines by `\n` and want to normalize them to be separated by `\r\n`.
     # This allows us to identify a former line end with `\r` (as the `\n` is not matched)
     # All results returned from this buffer are normalized to feature `\n` line endings.
-    message_parts.encode(crlf_newline: true).scan(SPLIT_INDIVIDUAL_LINES).each do |line|
+    normalized_line_endings(message_parts).scan(SPLIT_INDIVIDUAL_LINES).each do |line|
       # Same argumentation as above: We can always append (previous empty or invalid)
       buffer += line
 
@@ -70,6 +70,13 @@ class Runner::Connection::Buffer
     buffer
   end
 
+  def normalized_line_endings(string)
+    # First, we ensure line endings are only represented by `\n`, regardless of the original line ending.
+    # Then, we convert all line endings to `\r\n` to ensure we can identify the `\r` at the end of a line.
+    # This "double conversion" is required to prevent line endings with \r\r\n.
+    string.encode(universal_newline: true).encode(crlf_newline: true)
+  end
+
   def add_to_line_buffer(message)
     @buffering = false
     @global_buffer = +''